Diagnostic Test

READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN
1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
2. With the scan tool, run a Vehicle Scan Report or record the Environmental Data.
3. With the scan tool, erase DTCs.
4. Turn the ignition off for at least 10.0 seconds.
5. Turn the ignition on.
6. Using the recorded Environmental Data and the When Monitored Conditions, operate the vehicle in the conditions that set the DTC.
7. With the scan tool, read DTCs.
Did the DTC return?

Yes
- Go To 2
No
- Perform the TESTING FOR AN INTERMITTENT CONDITION diagnostic procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK THE (F10) HVAC BLOWER MOTOR FUSE AT THE INTERIOR POWER DISTRIBUTION CENTER (PDC)
NOTE:
DIAGNOSE AND REPAIR ALL LIN BUS RELATED DTC'S BEFORE PERFORMING THIS TEST PROCEDURE

At the Interior Power Distribution Center (PDC), check fuse status (blown, missing, etc.)

Was the fuse blown or missing?

Yes
- Replace the fuse.
- Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
No
- Go To 3
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 4
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 5
ISOLATE AND CHECK THE (C56) FRONT BLOWER PWM CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT AT THE HVAC MODULE HARNESS CONNECTOR
1. The ignition must be off when performing a resistance check to find a short between circuits.
2. Isolate the circuit by disconnecting the ECU and the component harness connectors containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit. Check the disconnected connectors and related harnesses for damage, corrosion, and loose fitting terminals.
3. Connect one lead of the DVOM to the circuit being tested at the ECU harness connector.
4. With the other lead of the DVOM probe all other circuits at the ECU harness connector.
NOTE:
When back-probing a circuit at a harness connector, always use an appropriate back probing tool to prevent damage to the connector terminals.

Is there continuity between the circuit being tested and any other circuit?

Yes
- Repair the circuit for a short to another circuit. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
- Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
No
- Go To 6
REPLACE THE BLOWER MOTOR POWER MODULE AND CHECK FOR THE DTC TO RETURN
1. Replace the Blower Motor in accordance with the Service Information. Refer to MODULE, POWER, REAR BLOWER MOTOR, REMOVAL AND INSTALLATION .
2. Connect the Blower Motor, ECU, and any other disconnected harness connectors.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Using the recorded Environmental Data and the When Monitored conditions, operate the vehicle in the conditions that set the DTC.
6. With the scan tool, read DTCs.
Did the DTC return?

Yes
- Go To 7
No
- Replacing the Blower Motor 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 .