General information
To supply power or control signal to some of the electrical consumers in the vehicle (such as fuel injection system components, horn, starter motor, cooling fan, fog lights and others) relays are used. In fact, the relay is an electrical key that provides the closure of the I / O circuit on a low voltage signal. In the event of a relay failure, the corresponding consumer fails to function. The relays are installed in the mounting block under the instrument panel and in the blocks in the engine compartment (see Specifications). A description of the check for proper functioning of the relay is given below. Failed relays must be replaced.
Examination
1. If it is not possible to find out how the relay is connected to the corresponding electrical circuit according to the wiring diagrams (Electrical equipment diagrams), it should be remembered that the approach to checking any relay is basically the same in all cases (see below).
2. In most cases, a control loop is always connected to two of the relay's contact terminals. When a low-voltage voltage is applied to these terminals, the current begins to circulate through the relay control winding, as a result of which the large contacts of the working circuit of the consumer of electricity are closed. The rest of the terminals are the terminals of the working (I/O) contour.
3. In order to facilitate the identification of the relay terminals, an explanatory marking is usually applied to its body with an image of the key connection diagram.
4. Before removing the relay, make sure that the corresponding circuit is de-energized.
5. Connect a fused jumper wire between one of the relay control terminals and the positive battery terminal. Using the second jumper wire, ground the second control terminal - the relay should make a click. Some relays require obligatory observance of the polarity of the connection - if there is no click, try changing the polarity of connecting the control terminals.
6. With jumper wires connected, check for continuity between the loop I/O terminals.
7. If the test fails, replace the relay.