Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
The power supply cord will read open due to an internal thermal switch if the ambient temperature is above -18°C (0°F).
- 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.