Circuit/System Testing
WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.
- Courtesy lamps the vehicle is equipped with
- Each component's control and ground circuit terminals
- Component locations on control circuit 157
- Ignition/vehicle OFF, disconnect the X2 and X5 connector at the K9 Body Control Module, ignition ON/vehicle in service mode.
- Verify the appropriate accent/courtesy lamps are not illuminated:
- E8A Front Side Door Sill Plate Illumination Lamp - Left
- E8B Front Side Door Sill Plate Illumination Lamp - Right
- E8D Front Side Door Courtesy Lamp - Driver
- E8P Front Side Door Courtesy Lamp - Passenger
- E8VA Front Floor Courtesy Lamp - Left
- E8VC Front Floor Courtesy Lamp - Right
- {With C70} E8VB Rear Floor Courtesy Lamp - Left
- {With C70} E8VD Rear Floor Courtesy Lamp - Right
- If an accent/courtesy lamp is illuminated
Repair the short to voltage on circuit 157.
- Go to next step: If all accent/courtesy lamps are not illuminated
- Connect a 3 A fused jumper wire between the appropriate control circuit terminal and B+:
- Terminal 1 - X2
- Terminal 5 - X5
- Verify the appropriate accent/courtesy lamps turn ON and OFF when connecting and disconnecting the jumper wire.
- If an accent/courtesy lamp is always OFF and the jumper fuse is OK.
- Test the appropriate ground circuit at the lamp for an open/high resistance.
- If an open/high resistance is found, repair the fault on the circuit or ground connection.
- Go to next step: If an open/high resistance is not found.
- Test circuit 157 for an open/high resistance.
- If an open/high resistance is found, repair the fault on the circuit
- Go to next step: If an open/high resistance is not found
- Replace the appropriate accent/courtesy lamp.
- If an accent/courtesy lamp is always OFF and the jumper fuse is open
- Test circuit 157 for a short to ground.
- If a short to ground is found, repair the fault on the circuit
- Go to next step: If a short to ground is not found
- Replace the appropriate accent/courtesy lamp.
- Go to next step: If the accent/courtesy lamps turn ON and OFF
- Replace the K9 Body Control Module.
NOTE:
Each component may need to be disconnected to isolate a short to voltage, short to ground, or an open/high resistance. Use the schematics to identify the following: