Circuit/System Testing

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.

Check the Water in Fuel lamp for proper operation. Refer to Water in Fuel Indicator Malfunction .

Disconnect the fuel heater harness connector from the top of the fuel filter/heater element housing.
Turn ON the ignition with the engine OFF.
Probe the fuel heater ignition 1 voltage circuit with a test lamp connected to a good ground.
- If the test lamp did not illuminate repair the short to ground or open in the ignition 1 voltage circuit.
Probe the fuel heater ground circuit at the fuel filter/heater element housing with a test lamp connected to battery voltage.
- If the test lamp did not illuminate repair the open in the ground circuit between the fuel filter/heater element housing and the engine ground.
Remove the fuel filter from the fuel filter/heater element housing. Test the ignition 1 voltage circuit and the ground circuit for an open in the fuel filter/heater element housing.
- If either circuit tested open replace the fuel heater element.
If all circuits test normal, test the fuel heater thermostatic switch for proper operation. Refer to Component Testing .