Circuit/System Testing
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet 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.