Circuit/System Testing
WARNING: This page is about a different car, the 2010 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the X2 harness connector K9 BCM.
- Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.
- If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
- Ignition OFF, connect the X2 harness connector K9 BCM
- Disconnect the harness connector at the E5A backup lamp listed below:
- X3 harness connector E5E tail lamp-left (Without T79)
- X1 harness connector E5E tail lamp-left (With T79)
- X3 harness connector E5F tail lamp-right (Without T79)
- X1 harness connector E5F tail lamp-right (With T79)
- Test for less than 30 Ω between the ground circuit terminal listed below and ground.
- E5E tail lamp-left (Without T79) ground terminal 2
- E5E tail lamp-left (With T79) ground terminal C
- E5F tail lamp-right (Without T79) ground terminal 2
- E5F tail lamp-right (With T79) ground terminal C
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Connect a test lamp between the control circuit terminal listed below and ground:
- E5E tail lamp-left (Without T79) control terminal 1
- E5E tail lamp-left (With T79) control terminal D
- E5F tail lamp-right (Without T79) control terminal 1
- E5F tail lamp-right (With T79) control terminal D
- Engine running, command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the selected states.
- If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
- If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
- If all circuits test normal, test or replace the E5A backup lamp-left and the E5B backup lamp-right.