Diagnostic Test

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 .

Turn the ignition off.

1. Disconnect the Blower Motor harness connector.
2. Connect a 12-volt test light between the (C56) PWM Control circuit and the (Z916) Ground circuit at the Blower Motor harness connector.
3. Turn the ignition on.
4. Operate the Blower Motor control through every speed position while observing the test light.
   NOTE:

   The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.

   NOTE:

   Note: Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

   NOTE:

   Note:  A 12-volt test light can be substituted for the load test tool, but only  if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.

   NOTE:

   Note: Why perform a Voltage Drop Test?  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:

   • 1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
   • 2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
   • 3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

   Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

   Courtesy of CHRYSLER GROUP, LLC

   NOTE:

   Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

   Did the load test bulb illuminate brightly when the Blower Motor controls where selected through every speed position?

   Yes 

   • Go To  3

   No 

   • Repair the 12.0 volt circuit for an open or high resistance. If the fuse is found to be open, check the circuit for a short to ground.
   • Perform the BODY VERIFICATION TEST.

     Refer to BODY VERIFICATION TEST .

1. The ignition must be off when checking the continuity of a circuit.
2. Isolate the circuit by disconnecting the Electronic Control Unit (HVAC) 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. Before testing a circuit, measure the resistance between the two leads of the Digital Volt-Ohm Meter (DVOM). Note:  Resistance in the meter leads can cause an error in the test results.
4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.
5. Connect the other lead to the circuit being tested at the HVAC harness connector and measure the resistance of the circuit.

Is the resistance below 3.0 Ohms?

Yes 

• Go To  4

No 

• Repair the circuit for an open or high resistance.
• Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .

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.

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  5

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, Electronic Control Unit (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  6

   No 

   • Replacing the Blower Motor corrected the condition.
   • Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .

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 .