Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This test resets the HVAC control module and checks for current air temperature actuator DTC.
-
The specified values are from the A/C System Performance Test.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The auxiliary air temperature cannot be adjusted from one or both auxiliary controls, or the auxiliary cooling is insufficient. | ||||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||
2 | The auxiliary HVAC control module 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 heating? | -- | Go to Step 3 | Go to Too Cold in Vehicle | ||||||||
Does the scan tool display DTC B0428 or B0429? | -- | Go to Step 4 | ||||||||||
4 | Place the auxiliary blower motor switch in each speed position. Does the auxiliary blower motor operate in each speed position? | -- | Go to Step 5 | |||||||||
5 | Does the auxiliary blower motor operate at the desired speeds? | -- | Go to Step 6 | |||||||||
6 | Does the Too Hot In Vehicle concern occur when A/C is desired? | -- | Go to Step 7 | Go to Step 8 | ||||||||
Perform the A/C system performance test. Refer to Air Conditioning (A/C) System Performance Test . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 8 | |||||||||
8 |
Does the scan tool indicate that the value of the Rear Temp Dr. offset parameter changes from the minimum specified value to the maximum specified value? | -4 to +4 | Go to Step 9 | Go to Step 13 | ||||||||
9 |
Does the scan tool indicate that the value of the Rear Temp Dr. Actual parameter changes from the minimum specified value to the maximum specified value? | 0-255 counts | Go to Step 10 | Go to Step 15 | ||||||||
10 | Inspect the auxiliary air temperature sensor for the following conditions.
Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 11 | ||||||||
11 |
Does the scan tool indicate that the sensor temperatures are within the specification at the thermometer temperatures? | -3 to +3°C (-5 to +5°F) | Go to Step 19 | Go to Step 12 | ||||||||
12 | Test the temperature sensor resistance. Does the resistance measure near the Sensor Resistance Table value? | -- | Go to Step 16 | Go to Step 14 | ||||||||
13 | 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 . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 17 | ||||||||
14 | Inspect for poor connections at the harness connector of the auxiliary air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 16 | ||||||||
15 | Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 18 | ||||||||
16 | Replace the air temperature sensor. Refer to Inside Air Temperature Sensor Replacement . Did you complete the replacement? | -- | Go to Step 19 | -- | ||||||||
17 | Replace the auxiliary HVAC control module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 19 | -- | ||||||||
18 | Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 19 | -- | ||||||||
19 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 | ||||||||
