Diagnostic Aids
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.
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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 the left and the right air temperature controls are diagnosed in this table. Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||||||||
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 Too Hot in Vehicle concern occur when A/C cooling is desired? | -- | Go to Step 5 | Go to Step 7 | ||||||||||
5 |
IMPORTANT:: For A/C compressor operation, the ambient air temperature must be above 3°C (38°F).
Does the A/C compressor operate? | -- | Go to Step 6 | |||||||||||
6 | Perform the refrigerant 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 18 | 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 18 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | ||||||||||
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 Wiring Repairs 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 control circuit of the air temperature actuator for an open, for a high resistance, for a short to ground, or for a 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 module connector is connected during this step in order to avoid misdiagnosis.
Is the voltage within the specified values with a smooth transition between cold and hot? | 0 V at cold 12 V at hot | Go to Step 13 | Go to Step 15 | |||||||||||
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 door and the air temperature actuator for the following conditions:
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 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 18 | Go to Step 17 | ||||||||||
16 | 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 18 | -- | ||||||||||
17 | Replace the HVAC control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. 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 | ||||||||||
