Engine Controls - System/Component Tests: Relays: Introduction

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

• Fuel pump relay
• Main relay
• Radiator (cooling) fan relay
• Mixture heater relay
• Neutral/park 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 internals. See appropriate WIRING DIAGRAMS article.