The numbers below refer to the step numbers on the diagnostic table.
The specified values are from the A/C System Performance Test.
The voltage will vary between 0-12 volts during normal operation. The HVAC control assembly connector must be connected during this step.
Step | Action | Value(s) | Yes | No | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: Temperature can not be adjusted, or cooling 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 in any of the speed positions? | -- | Go to Step 3 | Go to Blower Motor Inoperative | ||||||||||||
3 | Does the blower motor operate correctly for each speed position? | -- | Go to Step 4 | Go to Blower Motor Malfunction | ||||||||||||
4 |
Does air flow out of the selected HVAC outlet ducts? | -- | Go to Step 5 | Go to Air Delivery Improper | ||||||||||||
5 | When A/C is ON, does the customer concern occur? | -- | Go to Step 6 | Go to Step 8 | ||||||||||||
6 |
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 19 | Go to Step 9 | |||||||||||||
8 |
Does the air temperature actuator drive shaft rotate at all? | -- | Go to Step 9 | Go to Step 10 | ||||||||||||
9 | Inspect the air temperature door and the air temperature actuator for the following conditions:
Did you find and correct the condition? | -- | Go to Step 19 | Go to Testing for Intermittent Conditions and Poor Connections | ||||||||||||
10 | Test the ignition 3 voltage circuit of the air temperature actuator for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 11 | ||||||||||||
11 | Test the ground circuit of the air temperature actuator for an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 12 | ||||||||||||
12 | Test the air temperature door control circuit of the air temperature actuator for an open, high resistance, short to ground, or short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 13 | ||||||||||||
Important: Ensure that the HVAC control assembly connector is connected during this step in order to avoid misdiagnosis.
Does the voltage measure within the specified values with a smooth transition between COLD and HOT? | 0-12 V | Go to Step 15 | Go to Step 14 | |||||||||||||
14 | Test the ground circuit of the HVAC control assembly for an open. Refer to Circuit Testing and Wiring 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 air temperature actuator. 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 | ||||||||||||
16 | Inspect for poor connections at the harness connector of the HVAC control assembly. 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 | ||||||||||||
17 | Replace the air temperature actuator. Refer to Temperature Valve Actuator Replacement . Did you complete the replacement? | -- | Go to Step 19 | -- | ||||||||||||
18 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . 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 |