Step | Action | Values | Yes | No | ||||||||||||
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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 actuator operate correctly for each speed position? | -- | Go to Step 3 | Go to Blower Motor Malfunction | ||||||||||||
3 | Is the HVAC control assembly inoperative? | -- | Go to Step 16 | Go to Step 4 | ||||||||||||
4 | Inspect the cooling system for the following:
Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 5 | ||||||||||||
5 |
Does the A/C compressor operate? | -- | Go to Step 6 | |||||||||||||
6 |
Does the drive shaft of both air temperature actuators rotate? | -- | Go to Step 7 | Go to Step 8 | ||||||||||||
7 | Inspect the appropriate air temperature door and the appropriate air temperature door actuator for the following conditions:
Did you find and correct the condition? | -- | Go to Step 20 | |||||||||||||
8 | Test the position signal circuit of the appropriate temperature actuator for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 9 | ||||||||||||
9 | Test the low reference circuit of the appropriate temperature actuator for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 10 | ||||||||||||
10 | Test the 5-volt reference circuit of the appropriate air temperature actuator for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 11 | ||||||||||||
11 |
Does the test lamp illuminate in both positions? | -- | Go to Step 20 | Go to Step 12 | ||||||||||||
12 | 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 Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 13 | ||||||||||||
13 | Test the ignition 3 voltage circuit of the HVAC control module for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 16 | ||||||||||||
14 | Test the ground circuit of the HVAC control module for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 15 | Go to Step 17 | |||||||||||||
15 | Inspect the appropriate air temperature door for a mechanical condition or for a condition that allows excessive travel of the door. Did you complete the repair? | -- | Go to Step 20 | -- | ||||||||||||
16 | Inspect for poor connections at the harness connector of the appropriate 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 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 . Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 19 | ||||||||||||
18 |
Important: Perform the calibration procedure for the air temperature actuator. Replace the appropriate air temperature door actuator. Refer to Temperature Valve Actuator Replacement - Right Side Temperature Valve Actuator Replacement - Left Side . Did you complete the replacement? | -- | Go to Step 20 | -- | ||||||||||||
19 | Replace the HVAC control module. Refer to Heater and Air Conditioning Control 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 |