Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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The specified values are from the A/C System Performance Test.
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The voltage will vary between 0-12 volts during normal operation. The HVAC control module connector must be connected during this step.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
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 Inoperative | ||||||
3 | Does the blower motor operate at the correct speed in each speed position? | -- | Go to Step 4 | Go to Blower Motor Malfunction | ||||||
4 | Does the Too Hot in Vehicle concern occur when A/C cooling is desired? | -- | Go to Step 5 | Go to Step 7 | ||||||
5 |
IMPORTANT:: For A/C compressor operation, outside air temperature must be above 3°C (38°F).
Does the A/C compressor operate? | -- | Go to Step 6 | |||||||
Perform the A/C 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 18 | Go to Step 7 | |||||||
7 |
Does the air temperature actuator drive shaft rotate at all? | -- | Go to Step 8 | Go to Step 9 | ||||||
8 | Inspect the air temperature door and the air temperature actuator for the following:
Did you find and correct the condition? | -- | Go to Step 18 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | ||||||
9 | 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 in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 10 | ||||||
10 | Test the ground circuit of the air temperature actuator 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 18 | Go to Step 11 | ||||||
11 | Test the air temperature door position signal 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 in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 12 | ||||||
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Important: The HVAC control assembly must be connected to correctly perform tests.
Does the voltage measure within the specified values with a smooth transition between Cold and Hot? | 12 V at Cold 0 V at Hot | Go to Step 13 | Go to Step 15 | |||||||
13 | 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 in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 14 | ||||||
14 | Inspect the air temperature actuator, door and any attaching linkage for binding or a condition that prevents drive shaft rotation. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 16 | ||||||
15 | 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 in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 17 | ||||||
16 | Replace the air temperature actuator. Refer to Air Temperature Actuator Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- | ||||||
17 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- | ||||||
18 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 | ||||||
