Component Testing

WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Auxiliary Battery Relay and Run Relay (TP2)

Ignition OFF, disconnect the relay.
Test for 60-180 Ω between terminals 85 and 86.
- If not within the specified range, replace the relay.
Test for infinite resistance between the following terminals:
- 30 and 86
- 30 and 87
- 30 and 85
- 85 and 87
- If not the specified value, replace the relay.
Install a 20 amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2.0 Ω between terminals 30 and 87.
- If greater than specified range, replace the relay.