Scheme of the daytime running light control unit

Daytime running lights are not present on all cars, and the need for their presence forces motorists to install DGS on their own. According to Gosstandart, daytime running lights must switch on automatically when the engine is switched on, as well as turn off or reduce power on 50% when turning on the main headlights. Fulfillment of this condition is necessary for safe driving in the dark. It also eliminates the possibility of driving without headlights on, which is prohibited by traffic rules. These functions in the DHW system are performed by the daytime running light control unit.

DGS control unit

In addition to all that has been said, the presence of the control unit of the DHW allows you to save and instead of energy-intensive low beam headlights to use more economical lamps or LED strips. In our article we will consider several options, how to install a DHW control unit on your car, if not originally provided by the design. In particular, we will talk about the installation of the purchased control unit and the assembly of the relay control of running lights with their own hands.

Importantly: remember, that you are responsible for following all of the procedures below. If you are not confident in your abilities, we strongly recommend that you contact a specialized service center to install DHW in accordance with GOST.

Purchase of ready-made relay control panel

The use of such relays is the most convenient option for connecting DHW in accordance with GOST. The relay provides inclusion of running lights at engine start, as well as reducing their capacity by 30-50% when turning on the main headlights. These relays are equipped with fuses, which makes their use safe, and keeps your headlights from failing during power surges. The device is already sold assembled, your task is just to connect it correctly.

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The scheme of connection of DGZ through the relay

Making a control unit with your own hands

Certainly, the second option is suitable for those, who has experience in soldering and assembling chips. Assembling a relay according to the scheme of connecting DHW with your own hands will cost you much cheaper, than buying ready-made. To begin with, let's consider the algorithm of operation of a self-made relay.

Algorithm of action:

The circuit of the control unit receives power from the included ignition and starts to define work of the engine on activity of impulses, present on the ignition coil. If the pulses are present longer 5 seconds (corresponding to the started engine), DGZ turn on automatically. If there are no pulses during 5 seconds, DHS are turned off. Also, the running lights are automatically turned off when the main lighting is turned on.

Connection of the block of daytime running lights:

  • Power can be taken from anywhere in the grid, where it is present after turning the ignition key;
  • Impulses, according to which the scheme determines the operation of the engine, usually, taken from the ignition coil;
  • We take the signal of the main lighting from any point, in which voltage appears 12 volts from the inclusion of headlights;
  • At the output we connect any car relay, which meets the following conditions: current, which consumes the relay, should not be higher than 200mA at a voltage of 12V and an output current of 30-40A;
  • We throw a minus on the car body.

The advantage of this scheme is, that in the absence of separately installed DGS, we can connect them in parallel with a standard low beam control unit.

DGZ relay circuit

DHW relay with your own hands

The PIC12F629 microprocessor will be the best option for assembling your unit. Relatively inexpensive and affordable, this device will be the basis of our relay. A special programmer is used to program our controller, for example PICkit-2. The scheme of the block itself is not very complicated: the usual linear stabilizer is used, on inputs of which dividers on an input signal are established, secure with transistor switches. A field-effect transistor is installed at the output, connected to a conventional automotive transistor with a current of no more than 200mA.

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Visually, the scheme is as follows:

We will not go into detail in the process of soldering the chip itself. The algorithm is logical: model the board in any program for designing circuits, create a wiring diagram, if necessary, design a 3D model.

we select the case

As the case the case from any other automobile relay will ideally approach: desirable, so that the connector is on 6 contacts.

For security, the board must be varnished. CRAMOLIN ISOTEMP is ideal, this silicone coating is designed specifically for the insulation of various boards. For lovers of reinsurance, the board can be dressed in a heat-shrinkable tube.

When the preparation process is complete, you can insert the finished relay into the prepared housing. Most relays go on latches, so you will not have problems with tight fixing of all design.