Relays & Solenoids: Relays: Notes

A variety of relays are used and can be tested 2 different ways. The following relays can be tested using an ohmmeter and remotely supplied power and ground circuits:

• Electronic Control Module (ECM or ECCS) relay.
• Fuel pump relay.
• Main relay.
• Radiator (cooling) fan relay.
• Mixture heater relay.
• Park/neutral (inhibitor) relay.

Safety relays can be tested using an ohmmeter, voltmeter and remotely supplied power and ground circuits. All testing procedures require proper identification of relay internal circuits. See the WIRING DIAGRAMS article.