Automotive relays are electrical devices designed to close or open an electrical circuit under the influence of control signals or at certain time intervals. They serve to regulate the operation of equipment operating with high currents. How to connect a car relay correctly - read our article.
General provisions and common cases of relay application
Car owners often equip their cars with additional equipment. For example, they install a winch, a signal, a powerful spotlight, an alarm, or, for example, taximeter "Orion". All of these are high-amperage devices. And passing the entire power signal through the power button of this equipment is not only impractical, but also dangerous.
First, you will need a high-amperage switching device. A button or toggle switch for 30–40 amperes will be of impressive size and may not fit into the interior. Secondly, if the button is of insufficient power or abnormal overloads occur in the network, this can lead to a fire. Therefore, it is recommended to install a relay.
There are several basic rules regarding how to connect a car relay to ensure its normal functioning:
- The relay should only be connected through a suitable one according to the parameters. block, the output wires of which are connected to the electrical circuit by soldering or by crimping into special detachable terminals.
- The maximum current consumption of the connected equipment should not exceed the values indicated on the relay.
- A fuse with a current value not exceeding that indicated on the relay must be installed in the supply circuit before entering the relay.
- The control circuit is connected through a resistor with the parameters necessary to create the rated current from which the relay coil operates.
How to connect a four-pin automotive relay
Before starting work, you need to decide on the installation location of the relay and button, as well as the route for laying the wires. The relay must be located in an easily accessible place protected from environmental influences. As a rule, such a place is the space near the car's standard relay panel.
The relay is then fixed in the selected location. From it, the negative wire is connected to the terminal on the powered equipment, and the positive wire is connected through the supply contacts on the relay (usually marked with numbers 30 and 87). A fuse of suitable parameters must be placed in front of the relay.
The positive wire of the control circuit is connected through the contacts on the relay (in most cases they are numbers 85 and 86). To level out the induction surge after stopping the current supply, a diode is installed in the control circuit parallel to the contacts.
Before connecting the car four-pin relay, it is also necessary to establish what type it is: normally closed or normally open. This is important because normally closed relays constantly pass the power signal and turn off when current is applied to the control circuit. Normally open ones work the other way around: they close the circuit at the moment of switching on.
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We all know that when almost any mechanism operates, a certain amount of heat is generated. In everyday life, a similar phenomenon can most often be observed when the computer is running, and if it is not cooled in any way, the internal boards along with the contacts will simply melt. To prevent this from happening, the computer design includes a special fan designed to cool heated parts. In the automotive world, the main source of heat for a vehicle is its engine, so the need for its cooling arose almost simultaneously with the creation of this power unit.
Initially, the process of evolution of vehicle cooling systems followed two paths, which is why two types of cooling systems are installed on manufactured vehicles: air and liquid (hybrid). Since in both systems the final carrier, designed to dissipate the heat removed from the engine, is air, their design uses one common element - a fan. This device ensures constant and uniform heat removal into the atmosphere, thereby cooling the internal structural elements of a car engine.
1. Design and purpose of the engine cooling fan
The fan is located in the center of a certain casing, together with which it is installed on. The fan casing forms the air flow and does not allow it to dissipate, which is why this element can be considered one of the main components of the cooling system design. During its operation, the radiator exhibits some resistance to air flow, and if a fan is simply directed at it, then a certain part of the air will be reflected and bypass the device, as a result of which there will be no effective cooling.
As we have already said, a running engine is a powerful heat emitter, and To avoid overheating of the unit itself, this heat must be removed. The solution to this problem relies on various cooling systems.
For example, in a liquid engine cooling system, water or antifreeze is used as the main working element. The fluid circulates in the cylinder block and in the cylinder head, where it takes heat from the engine, thereby heating itself. Naturally, in order to successfully perform its duties, the coolant must release the heat it receives in order to perform the same function again. This is where the radiator comes into play.
The location of the radiator of the cooling system of a car engine allows it to “catch” flows of incoming air when the car is moving, which significantly accelerates heat transfer, which means the liquid cools faster. However, a car cannot be in motion all the time, therefore, in traffic jams or during long periods of parking, when the vehicle does not move, but its engine continues to work, the heat from the radiator is removed much worse, which often causes overheating of the engine with all the ensuing consequences. This result can also be obtained due to the vehicle moving at low speeds, especially on a hot summer day.
The fan located in front of the radiator prevents such situations and provides the engine with the necessary cooling. It turns on when the car is idle for a long time with the engine running, when the temperature in the cooling system becomes critical. The fan disperses the heat by passing the necessary air flow through the radiator, thereby dissipating the heat into the atmosphere.
Despite the importance of such a device, it has a fairly simple design and usually consists of three main elements: impellers(usually has four blades, but there may be more), casing And fan drive.
The fan drive, which ensures its rotation, can be of three types (on one machine, of course, only one of them is installed): mechanical, hydromechanical or electric.
The simplest option is a mechanical fan drive, in which rotation is transmitted via a belt drive. But in this case, the fan always rotates when the engine is running, which in some situations (for example, when starting a cold engine) causes extremely negative consequences. Therefore, this cooling method is no longer used on cars produced today.
A hydromechanical drive is considered more advanced, which uses a hydraulic or viscous coupling for operation. In the hydraulic version of this element, torque is transmitted or disconnected from the crankshaft by changing the amount of lubricating fluid. In a viscous coupling, silicone liquid is used for this purpose, and its viscosity depends on temperature indicators, the change of which gives the command to turn the fan drive on or off. To date, both species have not found widespread distribution, which is why they can be seen infrequently.
The most advanced, and at the same time, relatively simple type of fan drive is an electric drive, which sets the fan in motion using a simple electric motor connected to the vehicle's electrical system. Thanks to an electromechanical (used on older car models) and electronic (used on new) control system, a fan equipped with an electric drive can turn on and off when the temperature of the coolant changes. It can also rotate at different speeds under different operating modes of the vehicle’s power unit.
Nowadays, fans equipped with an electric drive type are most widely used, and this state of affairs is unlikely to change in the near future.
2. Installation and connection of the fan
Considering that cars are equipped with fans in normal mode, re-installation may only be necessary during repair work, that is, after replacing broken parts of an old part or when installing a new device. In addition, some car enthusiasts install an additional fan, which, in their opinion, can help better solve the problem of engine cooling.
Let's consider the option of installing an electrically driven fan in a situation where a part is completely replaced. So, in order to install a new device, you will first have to dismantle the old one. To do this, take a suitable socket wrench and slightly loosen the electric fan mounting bolts from below. Then, using the same key, unscrew the bolts securing the radiator tube that connects it to the air conditioning system (if, of course, such is provided for by the design of the car) and move it to the side.
Next, unscrew the upper and lower (already loosened) bolts securing the old fan, tilt it back a little and remove the part from the engine compartment. Now you need to disconnect the wiring harness from the fan casing. To do this, simply remove the wire harness from the clips located on the casing. While holding the impeller from rotating (you can use any convenient method), unscrew the nut securing it to the electric motor with a socket wrench, then, freeing it from the connection with the casing, simply remove it.
Installation of the new part is carried out in the reverse order, and most often the electric fan is replaced assembled with a new casing. Note! When installing the impeller on the axis of the electric motor, you need to align the groove located on the axis of the electric motor with the protrusion located on the hub of the impeller.
The fan can be connected in several ways: for example, through the ignition switch or through the coolant temperature sensor. In these cases, it should turn on when the ignition is turned on and when the antifreeze temperature is above 90 ° C, and the shutdown occurs either due to a decrease in the temperature of the specified fluid or when the ignition is turned off. Also, in parallel with the temperature sensor, some car owners recommend installing an additional switch (toggle switch), with which you can activate the fan at the driver’s request. If the temperature sensor breaks down, such an addition will help you get to the repair site without any problems, and in hot weather it will provide the opportunity to cool the engine in conditions of forced downtime with the engine running.
3. Refinement of the fan motor switching circuit
Many responsible car enthusiasts can spend hours in the garage, trying not only to fix existing problems, but also to prevent the occurrence of new problems through various improvements and modifications. The main goal of refining the electric fan switching circuit is to be able to force the fan to turn on and then operate stable, regardless of the position of the key or the temperature of the cooling liquid.
There are several ways to complete this task. Let's give an example of some of them. The first method is the most ideologically correct and least expensive. In this case, to force the engine cooling fan to turn on, it is enough to short-circuit one of the contacts of the black box to the housing, and when the radiator fan is activated, a “plus” should appear on the other contact of the black box.
The switch can be placed in any convenient place, for example, instead of the headlight washers or heated front seat switches.
The second method is more labor-intensive and expensive, but at the same time much more beautiful and elegant than the first. To implement it, at the initial stage it will be necessary to remove the instrument cluster cover, and a new fan switch relay, which has a special bracket for mounting the device, can be placed in the passenger compartment or in the engine compartment, but in the cabin it will probably be a little more convenient. Running wires into the interior is not a problem, and you can use the rubber plug for the headlight range control to complete the task. The "CHECK ENGINE" control lamp of the gearbox is perfect for the role of a light indicator for turning on the fan., and a diode soldered between them will help protect the contacts of the switching sensor from electromotive force (EMF).
To ensure that the circuits of the electric motor and the windings of its relay are protected by a fuse, a jumper is installed in the black box between the contacts, the material for which can be, for example, two male terminals and a piece of thick copper wire. Upon completion of work, all contacts should be treated with special lubricant.
In addition, when performing such modifications, it would be useful to clean and lubricate the fan motor, and if you also replace the standard impeller with four blades with a part with eight blades, then the air flow passing through the radiator will increase significantly, which means the cooling quality should improve.
We briefly described only two options for refining the circuit for switching on an electric radiator fan, but this is far from a final figure, because everything depends on the imagination of the car owner and the capabilities of his vehicle.
All the main electrical circuits and modifications for connecting the liquid cooling fan (CO) in VAZ cars of various models are provided. What is the essence of VO’s work? An electric motor with an impeller on a shaft is installed inside a rectangular metal frame, with which it is attached to the back of the radiator. When voltage (12 V) is applied to the contacts of the drive, it begins to work, rotating the blades and creating a directed stream of air, which, in fact, cools the antifreeze or antifreeze.
If the cooling fan does not work, do not rush to contact a car service. You can determine the cause of the malfunction yourself. Moreover, for this it is not at all necessary to have special skills - just study the reference material from website and follow the instructions to check/replace it.
Connection diagram for the VAZ 2104, 2105 and 2107 cooler
- radiator fan
- temperature sensor (located on the bottom of the radiator)
- mounting block
- ignition relay
- egnition lock
A - to contact “30” of the generator.
Electric cooling fan VAZ 2106
- electric motor switch sensor;
- fan motor;
- motor start relay;
- main fuse box;
- ignition switch;
- additional fuse box;
- generator;
- accumulator battery.
Fan connection 2108, 2109, 21099
Until 1998, on cars with the old mounting fuse block 17.3722 (finger type fuses), relay 113.3747 was included in the fan circuit. After 1998 there is no such relay.
Also, before 1998, the TM-108 switching sensor was used (the closing temperature of its contacts is 99±3ºС, the opening temperature is 94±3ºС), after 1998 the TM-108-10 with similar temperature ranges or its analogues from different manufacturers. The TM-108 sensor only works in conjunction with a relay; the TM-108-10, reinforced for high current, can work both with and without a relay.
Scheme for switching on the engine cooling fan on a VAZ 2109 with mounting block 17.3722
- Fan motor
- Motor start sensor
- Mounting block
- Ignition switch
K9 - Relay for turning on the fan motor. A - To terminal “30” of the generator
Scheme for switching on the engine cooling fan on a VAZ 2109 with mounting block 2114-3722010-60
- Fan motor
- Sensor 66.3710 for turning on the electric motor
- Mounting block
A - To terminal “30” of the generator
Connection diagram for VO VAZ 2110
The circuit diagram for switching on the cooling fan of the VAZ 2110 on carburetor and injection cars is different. On cars with a carburetor engine, a thermobimetallic sensor TM-108 is used for this, and on cars with an injection engine, control is carried out by a controller.
Diagram for 2113, 2114, 2115 injector and carburetor
Where is the fan relay located?
4 – electric fan relay;
5 – electric fuel pump relay;
6 – main relay (ignition relay).
Attention: the order of the relays and fuses can be arbitrary, we are guided by the color of the wires. Therefore, we find a relay from which comes a thin pink with a black stripe wire coming from the main relay (pin 85*) (not to be confused with the thin, red with a black stripe wire coming from the controller) and a thick power white with a black stripe wire (pin 87) (white and pink wires we need), this is the fan relay.
If the cooling fan does not work
To drive the fan, a DC electric motor with excitation from permanent magnets ME-272 or similar is installed. Technical data of the electric fan and fan switch sensor:
- Rated rotation speed of the electric motor shaft with impeller, 2500 – 2800 rpm.
- Electric motor current consumption, 14 A
- Sensor contact closure temperature, 82±2 degrees.
- Sensor contact opening temperature, 87±2 degrees.
The cooling system fan may not turn on due to:
- electric drive malfunctions;
- blown fuse;
- faulty thermostat;
- a failed thermal sensor for turning on the cooler;
- faulty VO relay;
- broken electrical wiring;
- faulty expansion tank plug.
To check the VAZ fan electric motor itself, we apply 12 V voltage from the battery to its terminals - a working motor will work. If the problem is with the fan, you can try to repair it. The problem is usually the brushes or bearings. But it happens that the electric motor fails due to a short circuit or break in the windings. In such cases, it is better to replace the entire drive.
The BO fuse is located in the mounting block of the car's engine compartment and is designated F7 (20 A). The test is carried out using a car tester turned on in probe mode.
- In a car with a carburetor engine you need to check the sensor - turn on the ignition and short-circuit the two wires going to the sensor. The fan should turn on. If this does not happen, the problem is definitely not with the sensor.
- For injection cars it is necessary to warm up the engine to operating temperature and disconnect the sensor connector, disconnecting it from the vehicle’s on-board network. In this case, the controller must start the fan in emergency mode. The electronic unit perceives this as a failure in the cooling system and forces the fan drive to operate in constant mode. If the drive starts, the sensor is faulty.
Replacing an electric fan in a car
- We park the car on a flat surface and immobilize it with the parking brake.
- Open the hood and disconnect the negative terminal.
- Using a 10mm wrench, unscrew the fastenings of the air filter housing.
- Using a screwdriver, loosen the air duct clamp on the air flow sensor and remove the corrugation.
- We unscrew the screws securing the cover of the air filter housing and remove the filter element.
- Using a size 8 wrench, unscrew the air intake mount and remove it.
- Using a 10mm wrench, then an 8mm wrench, unscrew the nuts securing the fan casing around the perimeter (6 pieces in total).
- Disconnect the wire block on the fan connector.
- Carefully remove the fan casing along with the drive.
- Using a 10mm wrench, unscrew the 3 bolts holding the electric motor to the casing.
- We put a new one in its place.
- We install the structure in place, fix it, and connect the connector.
- We carry out further installation in the reverse order.
Control circuit modernization
The cooling fan on the top ten turns on at a temperature of 100-105°C, whereas normal operating
The engine temperature is 85-90°C, so the fan turns on when the engine overheats, which naturally has a negative effect.
This problem can be solved in two ways: adjust the switch-on temperature in the “brains” or make a button. We'll focus on the second one. Turning on the fan from the button is very convenient: if you get into a traffic jam - turn it on, leave - turn it off, and no overheating.
A button for selecting the fan operating mode was installed in the cabin (always off, constantly on, automatically turned on via a sensor) - this “tuning” is not mandatory, but will be a very useful addition.
There will be a large current at relay contacts 87, 30, on the wire from the battery to the fuse and the fan ground, and therefore we must use wires there with a cross-section of at least 2 mm, otherwise the thinner wire will not withstand it and will burn out.
Video - connecting and checking VO
A single-phase voltage relay is used to protect household electrical appliances from unacceptable voltage surges in the electrical network. The device disconnects a house, apartment or separate load from the power supply, and when everything returns to normal, it automatically turns it back on. There are two main types of devices: with an automatic time delay before turning on and manually configured.
We connect various models
Voltage control relays are connected in different ways, depending on the model, characteristics and purpose.
Local protection
Socket relay
To protect one device (refrigerator, TV, computer), it is enough to purchase protection that can simply be plugged into an outlet. The procedure is as follows:
- We connect the power plug from our device to the relay.
- We plug our relay into the socket.
There may either be additional settings on the panel, or it may be an automatic device programmed at the factory. In this case, you don’t need to do anything else - turn it on and use it.
Note! These relays are not voltage stabilizers. If necessary, they must be purchased separately.
If the device has a settings panel, it must be properly configured. For correct settings, set the maximum and minimum operating voltage specified in the passport of the device that needs to be protected.
Extension
A protective relay, made in the form of an extension cord, works in the same way. The only difference is the number of sockets - there are several of them, which allows you to connect several consumers at the same time.
Comprehensive protection
Now let's figure out how to properly install and mount more complex models. They have one thing in common: they are installed in electrical panels next to the electric meter and power circuit breaker. The voltage relay connection diagram is very simple, but there may be nuances that we will pay attention to.
Basic actions:
- Using an indicator screwdriver, determine the phasing. As a rule, a “phase” comes out of the power machine, but it’s always worth double-checking.
- Turn off the machine and make sure there is no voltage.
One option: UZM
Connecting a relay of this type is carried out in several steps:
- After turning off the power circuit breaker, install the device on a DIN rail or fasten it using another method described in the passport.
- We determine the input - output.
- Marking meaning: INPUT - input, L - phase, N - zero. We connect the wires, observing the phasing.
- We also connect the ends to the output and bring them to the load.
The device is ready for operation, we supply power. Depending on the settings, it should enter operating mode after a certain time. This time can be hard-coded in the settings and cannot be adjusted, or it can be adjusted manually.
One way connection
The next type of protection devices looks different: all contacts are on one side, and there are not four, but three. Let's figure out how to install it and put it into operation. A general diagram for this type of voltage relay will help.
The first steps are the same as in the previous case: determine the phase, de-energize the circuit, make sure there is no voltage. Next we install the relay in its place. Switching is done as follows:
- Terminal 1 - working zero. The neutral wire from the circuit breaker fits here.
- Terminal 2 - input. We supply the phase with AB.
- Terminal 3 - output to load.
As you can see in the diagram, the wire from the machine comes to the first terminal and from there it goes further to the load. If the electrical panel is installed correctly, there should be a zero bus, then you won’t have to clamp two ends into one terminal. It will allow you to make as many branches as necessary and at the same time maintain reliable contact.
Model RN-104
This type of protective relay is connected in a completely different way. At first glance, it is no different from the previous one, but there are significant differences in the scheme. The key to understanding is the markings on the top of the case and the diagram drawn on the side. According to it, the input is terminal 1, the output is terminal 3. Contact number two is common. It is used both as a relay power input and as an output to the load.
When connecting this device with your own hands, you need to connect the “phase” wire to the leftmost contact, “zero” to the middle one. We connect another wire to the same bolt - to the load, and clamp both well. If there is a zero bus, we connect the wire from it to the middle contact, so there will be only one connection on this contact. Conductors go to the load from the extreme terminal of the device and from the zero bus.
Relay with multiple operating modes
We have just reviewed the simplest types of voltage control relay models, the connection of which does not cause any particular difficulties. It is worth paying attention to more complex developments. One of them is RN-113. This device can operate in several modes, so its connection diagram is slightly different.
Firstly, there are four bolts on the terminal block at the top. But these are double contacts: a pair on the left and a pair on the right. Such a feature.
Secondly, phasing does not matter here. Although it is most logical to break the phase - it is much safer when the consumer is in a disconnected state without voltage.
Thirdly, the power to the electronics is connected from above, and at the bottom there are switching contacts, which you need to pay special attention to: the device can have several operating modes. Let's look at the diagram.
After installation on the DIN rail (with the power breaker turned off), we connect the 220 volt input to pins 4-7. Then we clamp the phase wire to pin 3 (bottom). Now we need to decide what and how we want to protect.
If you need a normal mode - protection against high and low surges - we take the output from pin 2, as can be seen in the figure, position 1. The Umin and Umax switches on the relay body must both be turned on. We connect the neutral conductor directly to the load. Power can be supplied.
For undervoltage protection mode (only the Umin switch is turned on), the break phase is also connected to contacts 2–3.
Overvoltage protection (only Umax is included) - the phase wire is connected as in the figure, position 2 - terminals 1–3.
The fourth operating mode is automatic shutdown at voltages below 155 volts. Both switches are disabled and manual settings are disabled. The load is interrupted by contacts 2–3; after the emergency mode is eliminated, the return to operating mode occurs after a set time.
RN-112
This type of relay has a different connection type. The output contacts are independent of each other, the load connection depends on the selected functions. This device is more suitable for protecting specific equipment in home workshops, since it has an operating mode of 100 volts.
The device has three operating modes: voltage control below normal, above normal, and both modes simultaneously. On the top bar there are two contacts 1 and 2 - power supply.
To operate in general control mode (exceeding the maximum and minimum values), the lower right knob is turned with the arrow pointing up. The phase wire is connected to pin 5, the output to the load is taken from pin 6.
Undervoltage protection mode. Set the lower right knob to “min”. The load is also interrupted by contacts 5–6.
Protection against exceeding the permissible voltage value. We set the regulator to “max”, connect the load to contacts 3–4.
Setting operating modes
For normal operation of the voltage control relay, it is not enough to secure and connect it. Some models have settings displayed on the case - the maximum and minimum voltage at which the load will be de-energized, and the turn-on delay time. This option allows you to verify that the emergency situation has been resolved.
Factory settings are usually the following values: max - 250 V, min - 175 V, delay time - 5–15 seconds (each factory has its own way). It's best to leave it as is. But if there is a strong scatter in the network, causing frequent triggering, you can change the values by five volts, but no more.
Connecting multiple voltage monitoring relays
Technical conditions allow connection to a private house or apartment of three phases. If three-phase units are used to protect electrical equipment, then in the event of an emergency, all equipment on one branch will be de-energized, which is not very convenient. This problem is solved by three relays connected separately to each phase.
From the bottom terminal of the machine we make a connection to the input of the first block. From the other terminal - to the input of the next block. For ease of maintenance and repair, this should be done with multi-colored wires, while remembering that blue is always “zero”. We connect the neutral wire to the neutral bus.
You can install separate input circuit breakers so that, if necessary, de-energize the desired relay if you suddenly have to turn it off. As you can see, the installation is no different from the examples discussed above, only instead of one block there are three at once, each for its own phase.
We connect the relay outputs to automatic machines, which each go directly to their own load: lighting, sockets, boiler. Accordingly, each relay can be set to a different delay time.
If there is not enough power
There are often situations when it is necessary to install protective relays on powerful equipment, but the protective unit itself is not suitable according to the technical data. There is a way to increase the rated current by installing an intermediate relay. The idea is very simple: the load is connected to the network through a powerful contactor, the coils of which, in turn, are connected through a protective unit. As a result, the main load does not go through the relay, which is not overloaded.
The connection is carried out in the following sequence:
- We attach the protection relay and the starter to the DIN rail next to each other.
- When the power is turned off, we connect the “phase” and “zero” relays to the power input.
- Using a wire of the required cross-section, we connect the “phase” to the input of the breaker contact of the starter.
- The output of this contact is to the load. We take “zero” directly from the line.
- We connect two wires to the starter coil. We connect one to the zero bus, the other to the output of the breaking contacts of the protection relay (at the bottom of the device body).
- We connect the input of the relay breaking contacts to the phase wire of the network.
Now it is possible to control loads significantly exceeding the rated value of the protective relay.
Video on the topic
DRLs (daytime running lights) are additional lighting devices installed on a car for use during daylight hours. I would like to emphasize that DRLs are intended to indicate your vehicle in front of other road users, and not to provide additional illumination of the roadway. There is no doubt about the benefits of using DRLs; your car will become noticeable at a distance of several kilometers. This is achieved by using bright LEDs in the DRLs. In this article, I will tell you about the legal aspects of installing DRLs, as well as the various DRL wiring diagrams.
Legislation
Before practicing installing DRLs, I would like to dwell a little on the legal standards for installing DRLs, as well as the rules of their operation.
The very first and basic rule is that unauthorized installation of additional light signals on a car is prohibited. Yes, you are right, you do not have the right to install DRLs on your car if it was not equipped with them by the manufacturer. This will be considered as making changes to the design of the vehicle. For every change in the design of a vehicle, a certificate must be obtained, which in itself is neither quick nor cheap. Otherwise, traffic police officers will issue you a fine, or even take your car to the impound lot.
How so? My neighbor installed DRLs on the Oka and drives calmly! - you ask. He is simply lucky to have loyal traffic police officers who do not pay attention to his DRL - I will answer you.
Once again, unauthorized installation of additional light signals on a car is prohibited if it was not equipped with them by the manufacturer. Therefore, you make any changes to the design of the vehicle at your own peril and risk. It’s a completely different matter if your car’s equipment does not include DRLs, but the more expensive trim levels of your model do have DRLs. In this case, you have the right to install DRL without any approval from the certifying authorities.
The first rule for installing DRLs concerns their location on the car body (see picture). If we briefly describe this figure, we get the following:
- DRLs should be installed at a height of 250 to 1500 mm;
- The distance between adjacent edges of the DRLs must be at least 600 mm;
- The distance from the outer side surface of the vehicle to the nearby edge of the DRL should be no more than 400 mm.
Now let’s briefly go through the rules of operation and use of DRLs:
- DRLs should only be used during daylight hours;
- It is prohibited to use DRLs in conjunction with side lights, low and high beam headlights, as well as fog lights.
Everything that is not prohibited is permitted. It's that simple. Separately, I would like to dwell on an important point, it concerns the use of DRLs in conjunction with high beam headlights. The rule goes something like this: When the high beam signal is briefly signaled, with the side lights and low beam headlights turned off, the DRLs should not turn off. Let me break it down: you are driving with your headlights and side lights turned off, your DRLs are on, when you signal with your high beams to an oncoming car that you are approaching a traffic police post, your DRLs should not turn off.
Just? I also think that there is nothing complicated here. Knowing the legislation and rules for using DRLs, we are ready to move on to the practice of connecting them. Let's start with the simple and incorrect and end with the complex and correct. Go!
DRL connection diagram without relay
This is the simplest DRL connection diagram, but also the most incorrect. I'll describe it a little. With this connection scheme, you supply voltage to the DRLs from the main power circuit of the car. The main power circuit is activated when the key is turned in the ignition switch. Obviously, your DRLs will always work as long as the key is turned in the ignition, no matter what lighting you use. You have no way to turn off the DRLs until you remove the key from the ignition.
As you already know, the use of DRLs in conjunction with other lighting devices is prohibited. I do not recommend connecting DRLs using this scheme.
Connection diagram for DRL from oil pressure sensor
In this part we will tell you how to connect the DRLs so that they turn on when the engine starts. To connect according to this scheme, you will need a 4-pin relay. The principle of operation of the circuit is approximately the same. In the normal state, relay contacts 30 and 87 are open, i.e. no current passes between them, DRLs are turned off.
As soon as you start the engine, the oil pressure indicator light on the dashboard goes out, a signal from the oil pressure sensor arrives at relay contact 86, this signal excites the coil in the relay, which controls the closure of contacts 30 and 87. After the closure of contacts 30 and 87, your DRLs turn on . This scheme is also not correct because your DRLs will always work as long as your car's engine is running.
DRL connection diagram via 4-pin relay
To connect the DRL according to this scheme, you, as in the previous case, will need a 4-pin relay. Moreover, the connection diagram is absolutely identical to the previous case, only instead of the control signal from the oil pressure sensor, we will use a button in the car interior. Your DRLs will only turn on when you press a button in the cabin.
You can add a little automation to this scheme. In order for the DRLs to go off when the engine is stopped, you can send a signal to the button from the fuel pump, or from the same oil pressure sensor. This scheme already has the right to life, because you can control the DRL operation depending on your driving conditions.
The only downside is that you need to manually turn off the DRLs (press a button in the cabin) when you turn on the low beam headlights, and also manually turn on the DRLs when driving during daylight hours.
Connection diagram for DRL via 5-pin relay
This scheme is the most correct and automated; I recommend connecting the DRLs according to this scheme. This circuit uses a 5-pin relay. Let's talk a little about the operating principle of a 5-pin relay. The 5-pin relay has 2 power outputs. In the normal state, the first of the power terminals is closed, the second is open. After applying a control signal to the relay, the first output will become open and the second will become closed. This seems complicated, but let's look at an example and everything will become clear.
On the image:
- Contacts 85 and 86 are control contacts. Depending on whether there is voltage on them or not, contacts 87 or 87A close;
- Contact 30 – power supply contact of the relay. It is to this that voltage must be supplied to power consumers;
- Contacts 87 and 87A – contacts for connecting consumers.
Let me give you an example. There is no voltage on contacts 85 and 86; power through the relay goes to the consumer at contact 87A. There is voltage on pins 85 and 86, the relay switches power to the consumer on pin 87.
How to connect:
- We supply power to the DRLs and headlights through pin 30. For greater automation, take power from the main circuit of the car, which turns on when the ignition is turned on;
- We connect DRLs to contact 87A, which will always be on;
- We connect the headlights to pin 87, which will turn on only when the DRLs are turned off;
- To contacts 85 or 86 (it doesn’t matter), we apply a control signal from the headlights button in the cabin;
- We connect the remaining contact 85 or 86 to the car body.
With this connection, either the DRLs or the headlights may work. When the car is turned off, both the DRLs and headlights are turned off.
In my opinion, this is the ideal option.
