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.
IMPORTANT:
The heater cord with a thermal switch will read open if the ambient temperature is above -18°C (0°F). A heater cord without a thermal switch can be tested for an open at any temperature.
- Test the engine coolant heater for an open or short to ground.
- If open or shorted, replace the heater.
- If the heater tests normal, replace the coolant heater power cord.