Acura 39400-S10-003 Main Relay Assembly

Several electrical accessories in the vehicle, such as the fuel injection system, horns, starter, and cooling fans, utilize relays to transmit electrical signals to the components. Relays operate using a low-current control circuit to manage a high-current power circuit. A defective relay will prevent the associated component from functioning correctly. These relays are located in the engine compartment fuse box and various other spots throughout the vehicle. If a faulty relay is suspected, it can be removed and tested. For testing, it's advisable to consult the wiring diagram to identify the correct connections for the relay. Typically, two terminals correspond to the control circuit, connecting to the relay coil, while the remaining terminals are linked to the power circuit. Most relays are labeled to assist in identifying these terminals. To test, connect an ohmmeter to the power circuit terminals, then use a fused jumper wire to connect one control circuit terminal to the positive battery terminal and another jumper wire from the other control circuit terminal to ground. The relay should click, and continuity will be shown on the meter. If the relay does not click, reversing the jumper wires may be necessary due to polarity sensitivity. If the relay does not pass the test, it should be replaced.