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.
Ambient / Inside Air Temperature Sensor Circuit Malfunction
- Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
- Test for less than 1 ohm between the low reference circuit terminal B and ground.
- If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
- Ignition ON, verify the appropriate scan tool Temp Sensor parameter is greater than 4.9 volts or 250 counts.
- If less than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the HVAC control module.
- Install a 3-amp fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool Temp Sensor parameter is less than 0.1 volt or 5 counts.
- If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
- If all circuits test normal, test or replace the appropriate temperature sensor.
Duct Temperature Sensor Circuit Malfunction
- Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
- Test for less than 1.0 ohm between the low reference circuit terminal 2 and ground.
- If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
- Ignition ON, verify the appropriate Duct Temp Sensor Actual parameter is greater than 4.9 volts or 250 counts.
- If less than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the HVAC control module.
- Install a 3-amp fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool Duct Temp Sensor Actual parameter is less than 0.1 volt or 5 counts.
- If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
- If all circuits test normal, test or replace the appropriate temperature sensor.