Circuit/System Testing

NOTE:

Each component on the control circuit may need to be disconnected to isolate a short to voltage or short to ground. Use the schematics to identify the following:

Lighting components the vehicle is equipped with
Each component's control and ground circuit terminals
Component locations on the backlighting control circuit

Ignition OFF, disconnect the X5 harness connector at the K9 body Control Module, ignition ON.
Verify a test lamp illuminates between the B+ circuit terminal 4 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF.
2. Test for less than 2Ω in the B+ circuit end to end.
  - If 2Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2Ω, verify the fuse is not open and there is voltage at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF.
2. Test for infinite resistance between the B+ circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance, replace the K9 body Control Module.
- If the test lamp illuminates
Ignition OFF, connect the X5 harness connector at the K9 body Control Module.
Ignition OFF, all doors closed, all accessories OFF, disconnect the harness connectors at the components listed below.
- E37D dome/reading lamps - overhead console
- E37R dome/reading lamps - rear
- E8D door courtesy lamp - driver
- E8P door courtesy lamp - passenger
- E8J instrument panel courtesy lamp - left
- E8K instrument panel courtesy lamp - right
Test for less than 10Ω between the appropriate ground circuit terminal listed below and ground.
- E37D dome/reading lamps - overhead console terminal 6
- E37R dome/reading lamps - rear terminal 6
- E8D door courtesy lamp - driver terminal 2
- E8P door courtesy lamp - passenger terminal 2
- E8J instrument panel courtesy lamp - left terminal 2
- E8K instrument panel courtesy lamp - right terminal 2
- If 10Ω or greater
1. Ignition OFF.
2. Test for less than 2Ω in the ground circuit end to end.
  - If 2Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2Ω, repair the open/high resistance in the ground connection.
- If less than 10Ω
Connect a test lamp between the appropriate control circuit terminal listed below and ground.
- E37D dome/reading lamps - overhead console terminal 2
- E37R dome/reading lamps - rear terminal 2
- E8D door courtesy lamp - driver terminal 1
- E8P door courtesy lamp - passenger terminal 1
- E8J instrument panel courtesy lamp - left terminal 1
- E8K instrument panel courtesy lamp - right terminal 1
Verify the test lamp turns ON and OFF when commanding the Courtesy Lamps ON and OFF with a scan tool.
- If the test lamp is always OFF
1. Ignition OFF, disconnect the X2 harness connector at the K9 body control module.
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 2Ω in the control circuit end to end.
  - If 2Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2Ω, replace the K9 body control module.
- If the test lamp is always ON
1. Ignition OFF, disconnect the X2 harness connector at the K9 body control module, ignition ON.
2. Test for less than 1V between the control circuit terminal and ground.
  - If 1V or greater, repair the short to voltage on the circuit.
  - If less than 1V, replace the K9 body control module.
- If the test lamp turns ON and OFF
Test or replace the appropriate dome/courtesy lamp.