Relay function
If the command to turn on does not come from the switch, but from the devices of the mounting block in the engine compartment, the following happens: sensitive electronic devices cannot transmit high currents without the risk of damage.
When connecting the corresponding consumer, the supplied contact «86» the current closes in the relay on the contact «85» «masses».
In this case, the magnetic coil closes the contact, overcoming the resistance of the spring, and closes the circuit for «operating current».
«Operating current» in order to avoid a voltage drop, it is applied directly to the contact in the shortest possible way «30» relay and from there further - with closed contacts of the switch - through the contact «87» to the energy consumer.
There is also a contact «87a». It is firmly connected to the contact «87» and has the same function.
Relay Troubleshooting
1. Contact «30» must always be energized unless it is a relay whose consumer is dependent on another. For example: The fuel pump relay is energized only when the injection system is running.
2. To check the presence of voltage on the relay, remove it and use a contact probe with a lamp to check the contact «30» on the base of the relay. If there is no current, the wiring is faulty.
3. Remove the relay, contact «86» connect to the positive terminal of the battery, contact «85» - With «weight». The actuation of the contact in the magnetic coil of the relay must be clearly audible, otherwise the relay is faulty.
4. Help with a faulty relay: remove the relay from the contacts. Install a jumper in the contact board of the relay between the contact «30» And «87» from a paper clip or a short piece of wire. Thus, the corresponding energy consumer will be under constant voltage. To switch off, it is necessary to remove the jumper, since the corresponding switch in this case is blocked.