Circuit/System Testing

WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.

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:

Exterior courtesy lamps the vehicle is equipped with
Each component's control and ground circuit terminals
Component locations on the exterior courtesy lamps control circuit

Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the inoperative exterior courtesy lamp. It may take up to 2 min for all vehicle systems to power down.
Test for less than 10 Ω between the appropriate ground circuit terminal listed below and ground.
- E8YD Outside Rearview Mirror Courtesy Lamp - Driver terminal 1 X2
- E8YP Outside Rearview Mirror Courtesy Lamp - Passenger terminal 1 X2
- A24D Door Handle Assembly - Driver Exterior terminal 5
- A24P Door Handle Assembly - Passenger Exterior terminal 5
- A24LR Door Handle Assembly - Left Rear Exterior terminal 5 (Sedan)
- A24RR Door Handle Assembly - Right Rear Exterior terminal 5 (Sedan)
- If 10 Ω or greater
1. Ignition OFF.
2. Test for less than 2 Ω in the ground circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, repair the open/high resistance in the ground connection.
- If less than 10 Ω
Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON.
- E8YD Outside Rearview Mirror Courtesy Lamp - Driver terminal 1 X1
- E8YP Outside Rearview Mirror Courtesy Lamp - Passenger terminal 1 X1
- A24D Door Handle Assembly - Driver Exterior terminal 3
- A24P Door Handle Assembly - Passenger Exterior terminal 3
- A24LR Door Handle Assembly - Left Rear Exterior terminal 3 (Sedan)
- A24RR Door Handle Assembly - Right Rear Exterior terminal 3 (Sedan)
Verify the test lamp turns ON and OFF when commanding the Outside Rear View Mirror Courtesy Lamp ON and OFF with a scan tool.
- If the test lamp is always OFF
1. Ignition OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module.
  - X4 - Coupe
  - X7 - Sedan
2. Test for infinite resistance between the control circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the K9 Body Control Module.
- If the test lamp is always ON
1. Ignition OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module, ignition ON.
  - X4 - Coupe
  - X7 - Sedan
2. Test for less than 1 V between the control circuit terminal and ground.
  - If 1 V or greater, repair the short to voltage on the circuit.
  - If less than 1 V, replace the K9 Body Control Module.
- If the test lamp turns ON and OFF
Test or replace the exterior courtesy lamp.