Circuit/System Verification

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Verify cooling fan operation using the scan tool commands listed below:

Fan Relay 1 ON-Both fans run at low speed.
Fan Relays 2 and 3 ON-The right fan runs at high speed, the left fan is OFF.
Fan Relays 1, 2 and 3 ON-Both fans run at high speed.