2. Relays in the engine compartment can be identified by the designation on the holder cover. Not all relays listed may be applicable to a specific model (the inhibitor relay, for example, is installed only in cars with automatic transmission), some relays can have two functions. For example, the lamp control relay on cars with a carburetor is also the auto throttle relay.
3. The four relays located above the fuse panel vary according to model and year. Counting from left to right, on some models they control the following circuits:
- 1. Rear fog lights, rear window defroster, ignition, power windows,
- 2. Power window, optional, or rear fog lights, rear window defroster,
- 3. Ignition, additional, or rear fog lights, rear window heater. Additionally, a window with a power window, or ignition.
4. Relay electrically controlled switches. They are used for two main reasons:
- (a) The relay can switch large currents over a distance, thus allowing the use of low-power control switches and wiring,
- (b) A relay can control multiple circuits, unlike mechanical switches.
5. In addition, some relays have a "timer" function - for example, a window timer relay with a glass servo drive.
6. If the circuit or system serviced by the relay is damaged, always remember that the fault may also be in the relay. The test consists of substituting a serviceable unit. Beware of replacing relays that are outwardly identical but perform different functions.
7. Most of the adapted relays are from a standardized range of four types.
8. Replacing the relay involves removing it from the holder and installing a new one.