The numbers below refer to thew step numbers on the diagnostic table.
This step ensures that the primary HVAC system is functioning properly.
The DTC's listed could set if a calibration of the actuators is performed.
If the condition does not occur when an A/C request has been made then you must bypass the A/C performance test procedures.
Performing the Air Conditioning System Performance Test ensures that the A/C system is operating properly for further testing.
This step ensures that the rear auxiliary HVAC control module is able to move the auxiliary air temperature actuator.
This step ensures that the front auxiliary HVAC control assembly is able to move the auxiliary air temperature actuator.
The infrared sensor is located between the auxiliary blower motor switch and the auxiliary temperature switch on rear auxiliary HVAC control module. It has a glass cover protecting the sensor which is integral to the rear auxiliary HVAC control module.
Step | Action | Values | Yes | No |
---|---|---|---|---|
Schematic Reference: HVAC Schematics DEFINITION: Auxiliary air temperature can not be adjusted from one or both auxiliary controls or auxiliary cooling is insufficient. | ||||
1 | Did you perform the HVAC Diagnostic System Check? | -- | Go to Step 2 | |
The auxiliary HVAC control assembly cannot request A/C compressor operation. An A/C request must be generated by the HVAC control module to provide cooled airflow through the auxiliary system. Does the HVAC control module operate and provide sufficient cooling? | -- | Go to Step 3 | Go to Too Hot in Vehicle | |
Important:: If during this diagnostic procedure the HVAC control module is disconnected a recalibration of actuators must be performed to avoid misdiagnosis.
Does the scan tool display DTC B0229, B0414, B0434, B3761 or B3764? | -- | Go to Step 4 | ||
4 |
Does the auxiliary blower motor operate at all? | -- | Go to Step 5 | |
5 | Does the auxiliary blower motor operate at the desired speed in each speed position? | -- | Go to Step 6 | |
Does the Auxiliary Too Hot In Vehicle concern occur when A/C cooling is desired? | -- | Go to Step 7 | Go to Step 8 | |
Perform the refrigerant system performance test. Refer to Air Conditioning (A/C) System Performance Test . Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 8 | |
Do the counts change? | -- | Go to Step 9 | Go to Step 13 | |
Do the counts change? | -- | Go to Step 10 | Go to Step 14 | |
10 | Check the auxiliary upper outlet and auxiliary lower outlet temperature sensors for proper installation. Refer to Air Temperature Sensor Replacement - Upper Auxiliary and Air Temperature Sensor Replacement - Lower Auxiliary . Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 11 |
Place your hand directly over the infrared sensor on the rear auxiliary HVAC control module. Do the counts change? | -- | Go to Step 12 | Go to Step 18 | |
12 |
Does the resistance measure near the sensor resistance table value? | -- | System OK | Go to Step 16 |
13 | Test the low reference circuit of the front auxiliary HVAC control assembly for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 15 |
14 | Test the front auxiliary temperature door control circuit of the front auxiliary HVAC control assembly for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 15 |
15 |
Does the resistance change? | -- | Go to Step 18 | Go to Step 17 |
16 | Inspect for poor connections at the harness connector of the suspect air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 19 |
17 | Inspect for poor connections at the harness connector of the front auxiliary HVAC control assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 20 |
18 | Inspect for poor connections at the harness connector of the auxiliary HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 21 |
19 | Replace the suspect air temperature sensor. Refer to Air Temperature Sensor Replacement - Upper Auxiliary or Air Temperature Sensor Replacement - Lower Auxiliary . Did you complete the replacement? | -- | Go to Step 22 | -- |
20 | Replace the front auxiliary HVAC control assembly. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Front . Did you complete the replacement? | -- | Go to Step 22 | -- |
21 | Replace the auxiliary HVAC control module. Refer to Auxiliary Heater and Air Conditioning Control Module Replacement . Did you complete the replacement? | -- | Go to Step 22 | -- |
22 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 |