Circuit/System Testing
WARNING: This page is about a different car, the 2008 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns:
- Never open the high intensity discharge system ballast or the arc tube assembly starter.
- Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.
- Ignition OFF, remove the appropriate PRK LAMP Relay or RT PRK LAMP relay from the rear fuse block.
- Connect a test lamp between B+ and the appropriate relay control circuit terminal listed below.
- PRK LAMP relay terminal 101
- RT PRK LAMP relay terminal 92 - Japan, Korea, Taiwan only
- Ignition ON, command the Parking Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
- If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
- If the circuit tests normal, test or replace the park lamp relay.