Circuit/System Testing
WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
- With a scan tool clear the DTC.
- Ignition OFF, disconnect the harness connectors at the following components:
- Courtesy/reading lamp - left front
- Courtesy/reading lamp - left rear
- Courtesy/reading lamp - right front
- Courtesy/reading lamp - right rear
- Courtesy lamp - rear compartment
- I/P compartment lamp
- LH I/P courtesy lamp
- LH vanity mirror
- RH vanity mirror
- Operate the vehicle within the conditions for running the DTC and verify the DTC does not reset.
- If the DTC resets, test the courtesy lamps voltage supply circuit for a short to voltage, short to ground, or an open/high resistance. If the circuits test normal, replace the BCM.
- Reconnect each component one at a time and verify that the DTC does not reset as current.
- If the DTC resets as current, test or replace the component responsible for setting the DTC.