The numbers below refer to the step numbers on the diagnostic table.
This checks for proper cooling system operation.
If the voltage ranges from 0.5 volts to 4.5 volts then the air temperature actuator is able to rotate and the HVAC control module has the ability to command the air temperature actuator.
The voltage will vary between 0-12 volts during normal operation. The HVAC control module connector must be connected during this step. The voltage should be monitored while air temperature actuator is commanded to move.
Step | Action | Values | Yes | No | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: HVAC Schematics DEFINITION: The temperature cannot be adjusted, or the heating is insufficient. | ||||||||||||||||
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 in each speed position? | -- | Go to Step 4 | Go to Blower Motor Malfunction | ||||||||||||
4 | Turn the blower motor ON and select an air outlet mode. Is the air flow sufficient from the correct outlets in each mode? | -- | Go to Step 5 | Go to Air Delivery Improper | ||||||||||||
Inspect the cooling system for the following conditions:
Refer to Heating Performance Diagnostic in Heating, Ventilation and Air Conditioning. Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 6 | |||||||||||||
Does the voltage measure within the specified values with a smooth transition from the coldest position to the warmest position? | 0.5-4.5 V | Go to Step 7 | Go to Step 8 | |||||||||||||
7 | Inspect the air temperature door and the air temperature actuator for the following conditions:
Did you find and correct the condition? | -- | Go to Step 20 | System OK | ||||||||||||
8 |
Does voltage measure near the specified value? | 5 V | Go to Step 9 | Go to Step 13 | ||||||||||||
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 20 | Go to Step 10 | ||||||||||||
Does the voltage measure near specified value? | 1-12 V | Go to Step 16 | Go to Step 11 | |||||||||||||
11 | Test the air temperature door control A 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 20 | Go to Step 12 | ||||||||||||
12 | Test the air temperature door control B 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 20 | Go to Step 13 | ||||||||||||
13 | Test the air temperature actuator 5-volt reference 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 20 | Go to Step 14 | ||||||||||||
14 | Test the signal 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 20 | Go to Step 15 | ||||||||||||
15 | Test the low reference 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 20 | Go to Step 17 | ||||||||||||
16 | 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 20 | Go to Step 18 | ||||||||||||
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 20 | Go to Step 19 | ||||||||||||
18 | Replace the air temperature actuator. Refer to Air Temperature Actuator Replacement . Did you complete the replacement? | -- | Go to Step 20 | -- | ||||||||||||
19 | Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement? | -- | Go to Step 20 | -- | ||||||||||||
20 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 | ||||||||||||