The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||||||||||
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Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The temperature cannot be adjusted, or the heating is insufficient. | ||||||||||||||||
1 |
Important: Both the left and the right air temperature controls are diagnosed in this table. Did you perform the HVAC Diagnostic System Check? | -- | 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 in each speed position? | -- | Go to Step 4 | Go to Blower Motor Malfunction | ||||||||||||
4 | Except for the blower motor speed, are all of the functions of the HVAC control module inoperative? | -- | Go to Step 13 | Go to Step 5 | ||||||||||||
5 | Inspect the cooling system for the following conditions:
Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 6 | ||||||||||||
6 |
Does the A/C compressor operate? | -- | Go to Step 7 | |||||||||||||
7 |
Does the drive shaft of the air temperature actuator rotate? | -- | 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 22 | |||||||||||||
9 | Test the ignition 3 voltage circuit of the air temperature actuator for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 10 | ||||||||||||
10 | Test the ground circuit of the air temperature actuator for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 11 | ||||||||||||
11 | Test the door control circuit of the air temperature actuator for an open, a high resistance, a short to ground, or a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 12 | ||||||||||||
Important:: Ensure that the HVAC control module connector is connected during this step in order to avoid misdiagnosis.
Is the voltage measurement within the specified values with a smooth transition between cold and hot? | 0 V at cold 12 V at hot | Go to Step 17 | Go to Step 19 | |||||||||||||
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 to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 14 | ||||||||||||
14 | Test the battery positive voltage circuit of the HVAC control module for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 15 | ||||||||||||
15 | Test the blower motor control OFF circuit of the HVAC control module for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 16 | ||||||||||||
16 | Test the ground circuit of the HVAC control module for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 19 | ||||||||||||
17 | Inspect for poor connections at the harness connector of the air temperature actuator. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 22 | Go to Step 18 | |||||||||||||
18 | 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 22 | Go to Step 20 | ||||||||||||
19 | Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 21 | ||||||||||||
20 | Replace the air temperature actuator. Refer to Air Temperature Actuator Replacement - Right Side or to Air Temperature Actuator Replacement - Left Side . Did you complete the replacement? | -- | Go to Step 22 | -- | ||||||||||||
21 | Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement? | -- | Go to Step 22 | -- | ||||||||||||
22 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 |