Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. With the scan tool, read HVAC 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 HVAC DTCs.
  Did the DTC return?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITIONS TEST. Refer to STANDARD PROCEDURE .
CHECK THE HARNESS CONNECTORS FOR DAMAGE
1. Check for loose, damaged or corroded terminals on the A/C Compressor Solenoid harness connector and HVAC Module harness connector.
  Are there any loose or damaged terminals?
  
  Yes
  - Repair the harness connectors as necessary.
  No
  - Go to Step 3.
CHECK THE (C27) A/C COMPRESSOR CONTROL CIRCUIT FOR A SHORT TO GROUND
1. Turn the Ignition off.
2. Disconnect the HVAC Module harness connector.
3. Disconnect the A/C Compressor Solenoid harness connector.
4. Check for continuity to ground in the (C27) A/C Compressor Control circuit between pin 1 of the A/C Compressor Solenoid harness connector and pin 56 of the HVAC Module harness connector.
  Is there continuity to ground in the (C27) A/C Compressor Control circuit?
  
  Yes
  - Repair the (C27) A/C Compressor Control circuit for a short to ground.
  - Perform the HVAC VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 4
CHECK THE A/C COMPRESSOR CONTROL SOLENOID FOR PROPER OPERATION
1. Turn the Ignition off.
2. Replace the A/C Compressor Control Solenoid in accordance with the service information. Refer to COMPRESSOR, A/C, REMOVAL AND INSTALLATION .Perform the HVAC VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  Did the DTC reset after running the Verification Test?
  
  Yes
  - Go To 5
  No
  - Test complete.
CHECK RELATED HARNESS CONNECTIONS
1. Disconnect all HVAC Module 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 HVAC Module 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 HVAC Module DTCs.
  Did the DTC return?
  
  Yes
  - Replace the HVAC Module in accordance with the Service information. Refer to MODULE, HVAC, REMOVAL AND INSTALLATION .
  - Perform the HVAC VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Repair any faulty connections.
  - Perform the HVAC VERIFICATION TEST. Refer to STANDARD PROCEDURE .