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 2
  No
  - Perform the TESTING FOR AN INTERMITTENT CONDITION procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK FOR BATTERY OR CHARGING SYSTEM RELATED DTCS IN THE BODY CONTROL MODULE (BCM) AND POWERTRAIN CONTROL MODULE (PCM)
1. With the scan tool, check the BCM and PCM for Battery and Charging System DTCs.
  Are any Battery or Charging System DTCs set?
  
  Yes
  - Perform PCM DTC diagnostic procedure(s). or BCM DTC diagnostic procedures. Refer to DIAGNOSTIC CODE INDEX or BODY CONTROL MODULE (BCM) - DIAGNOSTIC CODE INDEX .
  No
  - Go To 3
CHECK THE HVAC MODULE FUSED B(+) CIRCUIT VOLTAGE
1. Start the engine and turn on the HVAC system with A/C at MAX and blower at full speed.
2. While back probing at the HVAC Module C1 harness connector, measure the voltage on the HVAC Module Fused B (+) circuit.
  Is the voltage above 9.5 Volts?
  
  Yes
  - Go To 4
  No
  - Repair the HVAC Module Fused B (+) circuit for an open or high resistance.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
CHECK THE HVAC MODULE GROUND CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the HVAC Module C1 harness connector.
3. Using a 12-volt test light connected to 12-volts, test the HVAC Module Ground circuit at the HVAC Module C1 harness connector.
  NOTE:
  The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
  
  Does the test light illuminate brightly?
  
  Yes
  - Go To 5
  No
  - Repair the HVAC Module Ground circuit for an open or high resistance.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
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 HVAC VERIFICATION TEST .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .