The numbers below refers to the step number in the diagnostic table.
To request A/C operation the primary HVAC controls must be set to enable the A/C compressor.
If the test light remains illuminated the answer is No.
The primary HVAC control module controls the coolant bypass valve. It receives a Class 2 message from the auxiliary HVAC control module for the proper position of valve.
Step | Action | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The auxiliary temperature cannot be adjusted, or the auxiliary cooling is insufficient during A/C operation. | |||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||||
2 |
Does the scan tool display DTC B0145, B0428, or B3531? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 | ||||||
3 |
Does the scan tool indicate the Rear Temp. Select Sw. parameter increase from 1-13 counts? | Go to Step 4 | Go to Step 18 | ||||||
4 |
Does the auxiliary blower motor operate in any of the speed positions? | Go to Step 5 | |||||||
5 | Does the auxiliary blower motor operate at the desired speed? | Go to Step 6 | |||||||
6 | Does the customer concern occur when the A/C is OFF? | Go to Step 9 | Go to Step 7 | ||||||
Important: Ambient air temperature must be above 3°C (36°F).
Does the A/C compressor operate? | Go to Step 8 | ||||||||
8 | Perform the refrigerant system performance test. Refer to Air Conditioning (A/C) System Performance Test in Heating, Ventilation and Air Conditioning. Did you find and correct the condition? | Go to Step 21 | Go to Step 9 | ||||||
9 |
Does the Air Mix Door Actual parameter counts change? | Go to Step 10 | Go to Step 19 | ||||||
10 |
Does the inlet hose feel warmer than the outlet hose of the coolant bypass valve? | System OK | Go to Step 11 | ||||||
Does the test lamp illuminate on and off with each command? | Go to Step 12 | ||||||||
12 | Does the test lamp remain illuminated when commanded to OFF? | Go to Step 15 | Go to Step 13 | ||||||
13 |
Does the test lamp illuminate with each command? | Go to Step 16 | Go to Step 14 | ||||||
14 | Test the coolant bypass solenoid control circuit of the coolant bypass valve for one of the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 21 | Go to Step 17 | ||||||
15 | Test the coolant bypass solenoid control circuit of the coolant bypass valve for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 21 | Go to Step 18 | ||||||
16 | Repair the ground circuit of the coolant bypass valve. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 21 | -- | ||||||
17 | 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 in Wiring Systems. Did you find and correct the condition? | Go to Step 21 | Go to Step 19 | ||||||
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 21 | Go to Step 20 | ||||||
Replace the HVAC control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 21 | -- | |||||||
20 | Replace the auxiliary HVAC control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 21 | -- | ||||||
21 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |