Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. With the scan tool, read 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 Module DTCs.
  Did the DTC return?
  
  Yes
  - Go To 3
  No
  - Go To 2
PERFORM HVAC ACTUATOR CALIBRATION TEST AND RECHECK DTCS
1. With the scan tool, perform the HVAC Actuator Calibration Test and recheck DTCs.
  Did the DTC return?
  
  Yes
  - Go To 3
  No
  - Perform the TESTING FOR AN INTERMITTENT CONDITION procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK THE (C27) A/C COMPRESSOR CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the HVAC Module C1 harness connector.
3. Disconnect the A/C Compressor harness connector.
4. Turn the ignition on.
5. Measure the voltage on the (C27) A/C Compressor control circuit at the A/C Compressor harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the (C27) A/C Compressor control circuit for a short to voltage.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
  No
  - Go To 4
CHECK THE (C27) A/C COMPRESSOR CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
1. Check for continuity between the (C27) A/C Compressor Control circuit and all other circuits at the HVAC Module C1 harness connector.
  Is there continuity between the (C27) A/C Compressor Control circuit and any other circuit?
  
  Yes
  - Repair the circuit for a short to another circuit.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
  No
  - Go To 5
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 .
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .