Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit Description
The ignition relay is normally an open relay. The relay armature is held in the open position by spring tension. When the ignition switch is turned to the RUN or START position, current will flow through the relay coil. A wire connected to the other end of the relay coil completes the path to ground. The electromagnetic field created by the relay coil overcomes the spring tension and moves the armature, allowing the relay contacts to close.
The closed relay contacts allow current to flow from the battery to the ENG CONTROLS fuse, Fuel INJ fuse, ELEC ENG fuse, O2 Sensors fuse, TRANS SOL fuse, ABS fuse and AWD fuse. Fuses are located in underhood fuse/relay block. See Fig 1 .
When the ignition switch is turned off, the electromagnetic field collapses. This action allows the spring tension to move the armature away from the relay contacts, which interrupts current flow to the fuses.
If ignition relay fails to close, the engine will crank but will not run. The class 2 communications will be available with the use of a scan tool.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.