Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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This checks for proper cooling system operation.
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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 DEFINITION: Temperature can not be adjusted or heating insufficient. | ||||||||||||||||
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 | Turn the blower motor fan ON and select an air outlet mode. Does air flow out of the selected HVAC outlet ducts. | -- | Go to Step 5 | Go to Air Delivery Improper | ||||||||||||
Inspect the cooling system for the following:
Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 6 | |||||||||||||
6 |
Does the A/C compressor operate? | -- | 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 conditions:
Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 9 | ||||||||||||
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 a 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. 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 control 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:: 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 13 | |||||||||||||
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 Temperature Valve 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 | ||||||||||||
