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.
- Ignition OFF, disconnect the theft deterrent module (TDM) harness connector.
- Measure and record the voltage at the battery terminals. Ignition in ON position, measure the voltage between the accessory voltage circuit and the ground circuit of the TDM. Verify that the voltage readings do not differ more than 1 volt.
- If greater than 1 volt, test the accessory voltage circuit and the ground circuit of the TDM for an open/high resistance. If the circuits test normal, replace the TDM.
- Refer to Charging System Test .