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.
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 INTERMITTENT CONDITIONS procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK FOR VOLTAGE ON THE (F926) FUSED IGNITION SWITCH OUTPUT (RUN) CIRCUIT
1. Turn the ignition off.
2. Disconnect the Headlamp Switch harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (F926) Fused Ignition Switch Output (Run) circuit at the Headlamp Switch harness connector.
  Is there any voltage present?
  
  Yes
  - Go To 3
  No
  - Go To 7
CHECK THE (M9) HEADLAMP SWITCH SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Measure the voltage on the (M9) Headlamp Switch Signal circuit at the Headlamp Switch harness connector.
  Is the voltage above 5.2 volts?
  
  Yes
  - Go To 8
  No
  - Go To 4
CHECK THE (Z209) GROUND CIRCUIT FOR CONTINUITY TO GROUND
1. Turn the ignition off.
2. Check for continuity between ground and the (Z209) Ground circuit at the Headlamp Switch harness connector.
  Is there continuity between ground and the (Z209) Ground circuit?
  
  Yes
  - Go To 5
  No
  - Go To 9
CHECK THE BCM FOR PROPER OPERATION
1. Turn the ignition off.
2. Connect a jumper wire between the (Z209) Ground circuit and the (M9) Headlamp Switch Signal circuit at the Headlamp Switch harness connector.
3. Turn the ignition on.
4. With the scan tool, read BCM DTCs.
  Is DTC: B1050-11-COLUMN SWITCH MODULE MAIN LIGHTS-CIRCUIT SHORT TO GROUND set as Active?
  
  Yes
  - Replace the Headlamp Switch in accordance with the Service Information. Refer to SWITCH, HEADLAMP, REMOVAL AND INSTALLATION .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 6
CHECK THE (M9) HEADLAMP SWITCH SIGNAL CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the BCM C8/H harness connector.
3. Measure the resistance of the (M9) Headlamp Switch Signal circuit between the Headlamp Switch harness connector and the BCM C8/H harness connector - terminal 42.
  Is the resistance above 3.0 Ohms?
  
  Yes
  - Repair the open in the (M9) Headlamp Switch Signal circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 10
CHECK (F926) FUSED IGNITION SWITCH OUTPUT (RUN) CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the BCM C7/G harness connector.
3. Measure the resistance on the (F926) Fused Ignition Switch Output (Run) circuit between the Headlamp Switch harness connector and C7/G harness connector - terminal 13.
  Is the resistance above 3.0 Ohms?
  
  Yes
  - Repair the open or high resistance on the (F926) Fused Ignition Switch Output (Run) circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Remove and inspect the F49 (7.5A) Fuse for an open.
  - If Fuse Is Open: Replace the F49 (7.5A) Fuse. If the fuse continues to open, inspect and repair the (F926) Fused Ignition Switch Output (Run) circuit for a short to ground. If a short to ground is not found, Go To 10
  - If Fuse Is OK: Go To 10
CHECK THE (M9) HEADLAMP SWITCH SIGNAL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT IN THE HARNESS CONNECTOR
1. Turn the ignition off.
2. Disconnect the BCM C8/H harness connector.
3. Check for continuity between the (M9) Headlamp Switch Signal circuit and all other circuits on the Headlamp Switch harness connector.
4. Check for continuity between the (M9) Headlamp Switch Signal circuit and all other circuits on the BCM C8/H harness connector.
  Is there continuity between the (M9) Headlamp Switch Signal circuit and any other circuit(s)?
  
  Yes
  - Repair the short between the (M9) Headlamp Switch Signal circuit and the circuit that has continuity.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 10
CHECK THE (Z209) GROUND CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the BCM C8/H harness connector.
3. Measure the resistance on the (Z209) Ground circuit between the Headlamp Switch harness connector and C8/H harness connector - terminal 51.
  Is the resistance above 3.0 Ohms?
  
  Yes
  - Repair the open or high resistance on the (Z209) Ground circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 10
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. Reconnect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Reconnect 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.