The Mitsubishi scroll type A/C compressor carries an internal thermal cut off switch. The thermal cut off switch normal operation is to open and disable the compressor under extreme load and temperatures above 155°C (311°F). The internal thermal cut off switch is non-serviceable.
The number below refers to the step number on the diagnostic table.
Step | Action | Value(s) | 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 cooling is insufficient during A/C operation. | ||||||||||||||||
1 |
Important: Both left (driver) and right (passenger) air temperature control concerns 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 |
Does the recirculation door move to the correct position for each selection? | -- | Go to Step 5 | |||||||||||||
5 | Does the Too Hot in Vehicle concern occur when A/C cooling is desired? | -- | Go to Step 6 | Go to Step 8 | ||||||||||||
6 |
Important: The ambient air temperature must be above 3°C (38°F).
Does the A/C compressor operate? | -- | Go to Step 7 | |||||||||||||
7 | 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 19 | Go to Step 8 | ||||||||||||
8 |
Does the left and right air temperature actuator drive shaft rotate? | -- | Go to Step 9 | Go to Step 10 | ||||||||||||
9 | Inspect the left and right air temperature door and the left and right air temperature actuator for the following conditions:
Did you find and correct the condition? | -- | Go to Step 19 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | ||||||||||||
10 | Test the ignition 3 voltage circuit of the suspect 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 19 | Go to Step 11 | ||||||||||||
11 | Test the ground circuit of the suspect 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 19 | Go to Step 12 | ||||||||||||
12 | Test the air temperature door control circuit of the suspect 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 19 | Go to Step 13 | ||||||||||||
Important: Ensure that the HVAC control module 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? | 0.25 V at cold 14.7 V at hot | Go to Step 14 | Go to Step 16 | |||||||||||||
14 | 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 19 | Go to Step 15 | ||||||||||||
15 | 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 19 | Go to Step 17 | ||||||||||||
16 | 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 19 | Go to Step 18 | ||||||||||||
17 | Replace the air temperature actuator. Refer to Air Temperature Actuator Replacement - Right Side or Air Temperature Actuator Replacement - Left Side . Did you complete the replacement? | -- | Go to Step 19 | -- | ||||||||||||
18 | Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement? | -- | Go to Step 19 | -- | ||||||||||||
19 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 |