The numbers below refer to the step numbers on the diagnostic table.
The HVAC control module is inoperative when the module does not respond to an operator control request.
If the condition does not occur when an A/C request has been made, then you must bypass the A/C performance test procedures.
These actions are the enable criteria for the A/C compressor to operate. Ambient air temperature must be above 3°C (38°F) in order for this A/C compressor test to be run.
Performing the Air Conditioning System Performance Test ensures that the A/C system is operating properly for further testing.
If no condition is found with all conditions listed, then compare door travel to a known good vehicle.
Step | Action | Values | Yes | No | ||||||||||||
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Schematic Reference : HVAC Schematics DEFINITION: The temperature cannot be adjusted, or the cooling is insufficient during A/C operation. | ||||||||||||||||
1 | Did you review the HVAC operation and perform the necessary inspections? | -- | Go to Step 2 | |||||||||||||
2 |
Does the blower motor operate at all? | -- | Go to Step 3 | Go to Blower Motor Malfunction | ||||||||||||
3 | Does the blower motor operate correctly for each speed position? | -- | Go to Step 4 | Go to Blower Motor Malfunction | ||||||||||||
Is the HVAC control assembly inoperative? | -- | Go to Step 15 | Go to Step 5 | |||||||||||||
Does the Too Hot in Vehicle concern occur when A/C cooling is desired? | -- | Go to Step 6 | Go to Step 8 | |||||||||||||
Important: For A/C compressor operation, the ambient air temperature must be above 3°C (38°F).
Does the A/C compressor operate? | -- | Go to Step 7 | ||||||||||||||
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 | |||||||||||||
8 |
Does the drive shaft of both air temperature actuators rotate? | -- | Go to Step 9 | Go to Step 10 | ||||||||||||
Inspect the appropriate air temperature door and the appropriate air temperature actuator for the following conditions:
Did you find and correct the condition? | -- | Go to Step 22 | Go to Testing for Intermittent Conditions and Poor Connections | |||||||||||||
10 | Test the position signal circuit of the appropriate temperature actuator for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 11 | ||||||||||||
11 | Test the low reference circuit of the appropriate temperature actuator for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 12 | ||||||||||||
12 | Test the 5-volt reference circuit of the appropriate temperature actuator for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 13 | ||||||||||||
13 |
Does the test lamp illuminate in both positions? | -- | Go to Step 17 | Go to Step 14 | ||||||||||||
14 | Test the temperature door control A and temperature door control B circuits of the appropriate temperature actuator for an open, a high resistance, a short to ground, or a short to voltage. Refer to Circuit Testing and to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 19 | ||||||||||||
15 | Test the ignition 3 voltage circuit of the HVAC control module for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs . Did you find and correct the condition? | Go to Step 22 | Go to Step 16 | |||||||||||||
16 | Test the ground circuit of the HVAC control module for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 22 | -- | ||||||||||||
17 | Inspect for poor connections at the harness connector of the appropriate air temperature actuator. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs . Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 18 | ||||||||||||
18 | Inspect the appropriate air temperature actuator, the door, and any attaching linkage for binding or for a condition that prevents drive shaft rotation. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 20 | ||||||||||||
19 | Inspect for poor connections at the harness connector of the HVAC control assembly. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs . Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 21 | ||||||||||||
20 |
Important: Perform the calibration procedure for the air temperature actuator. Replace the appropriate air temperature actuator. Refer to Temperature Valve Actuator Replacement - Right Side Temperature Valve Actuator Replacement - Left Side . Did you complete the replacement? | -- | Go to Step 22 | -- | ||||||||||||
21 |
Important: Perform the calibration procedure for the HVAC control assembly. Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control 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 |