Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. With the scan tool, read Body Control Module (BCM) DTCs and record on the repair order.
2. Record the Environmental Data and any DTCs.
3. With the scan tool, erase DTCs.
4. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
5. With the scan tool, read BCM DTCs.
  Did the DTC return?
  
  Yes
  - Go To 2
  No
  - Perform the TESTING FOR AN INTERMITTENT CONDITION procedure. Refer TESTING FOR AN INTERMITTENT CONDITION to STANDARD PROCEDURE .
CHECK THE (M59) COURTESY LAMP FEED CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the Cargo Lamp harness connector.
3. Disconnect the Cargo Lamp 2 harness connector.
4. Check for continuity between ground and the (M59) Courtesy Lamp Feed circuit at the Cargo Lamp harness connector.
  Is there continuity between ground and the (M59) Courtesy Lamp Feed circuit?
  
  Yes
  - Repair the short to ground on the (M59) Courtesy Lamp Feed circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 3
CHECK THE BCM COURTESY LAMP OUTPUT
1. Turn the ignition on.
2. Turn the Courtesy Lamps on.
  NOTE:
  The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
3. Connect a test light between ground and the (M59) Courtesy Lamp Feed circuit at the Cargo Lamp harness connector.
4. Connect a test light between ground and the (M59) Courtesy Lamp Feed circuit at the Cargo Lamp 2 harness connector.
  Does the test light illuminate brightly for both connections?
  
  Yes
  - Replace the inoperative Cargo Lamp or Cargo Lamp 2 in accordance with the Service Information. or. Refer to LAMP, COURTESY, REMOVAL AND INSTALLATION . Refer to LAMP, DOME, REMOVAL AND INSTALLATION .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 4
CHECK THE (M59) COURTESY LAMP FEED CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the BCM C5/E harness connector.
3. Measure the resistance of the (M59) Courtesy Lamp Feed circuit between the Cargo Lamp harness connector and BCM C5/E harness connector - terminal 28.
4. Measure the resistance of the (M59) Courtesy Lamp Feed circuit between the Cargo Lamp 2 harness connector and BCM C5/E harness connector - terminal 28.
  Is the resistance above 3.0 Ohms for any of the connections?
  
  Yes
  - Repair the open or high resistance on the (M59) Courtesy Lamp Feed circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 5
CHECK RELATED HARNESS CONNECTIONS
1. Disconnect all BCM harness connectors.
2. Disconnect all related in-line harness connections (if equipped).
3. Disconnect the related component harness connectors.
4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Perform a terminal drag test on each connector terminal to verify proper terminal tension.
  Repair any conditions that are found.
5. Connect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. With the scan tool, erase DTCs.
9. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
10. With the scan tool, read BCM DTCs.
  Did the DTC return?
  
  Yes
  - Replace the Body Control Module (BCM) in accordance with the Service Information. Refer to MODULE, BODY CONTROL (BCM), REMOVAL AND INSTALLATION .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  - Test complete.