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 THE (C56) FRONT BLOWER PWM CONTROL CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Turn the Ignition off.
2. Disconnect the Blower Motor Power Module C2 harness connector.
3. Turn the Ignition on.
4. With a DVOM, check the (C56) Front Blower PWM Control circuit at the Blower Motor Power Module C2 harness connector.
  NOTE:
  PWM readings may not be steady on a DVOM, depending on the duty cycle that is being commanded.
  
  Dose the DVOM show a voltage reading?
  
  Yes
  - Go To 3
  No
  - Repair the circuit for an open.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
CHECK THE (C56) FRONT BLOWER PWM CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Blower Motor Power Module C2 harness connector.
3. Disconnect the HVAC Module C1 harness connector.
4. Turn the ignition on.
5. Measure voltage on the (C56) Front Blower PWM Control circuit at the HVAC Module C1 harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the circuit for a short to voltage.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
  No
  - Go To 4
CHECK THE (C56) FRONT BLOWER PWM CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
1. Check for continuity between the (C56) Front Blower PWM Control circuit and all other circuits at the HVAC Module harness connector.
  Is there continuity between the (C56) Front Blower PWM 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
REPLACE THE BLOWER MOTOR POWER MODULE AND CHECK FOR THE DTC TO RETURN
1. Replace the Blower Motor Power Module in accordance with the Service Information. Refer to MODULE, POWER, BLOWER MOTOR, REMOVAL AND INSTALLATION .
2. With the scan tool, erase DTCs.
3. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
4. With the scan tool, read HVAC Module DTCs.
  Did the DTC return?
  
  Yes
  - Go To 6
  No
  - Replacing the Blower Motor Power Module corrected the condition.
  - 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 .