Circuit/System 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.
Check the Water in Fuel lamp for proper operation. Refer to Water-in-Fuel Lamp Always On .
- 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 below.