Compressor Clutch Does Not Engage
TEST DESCRIPTIONSteps 1-7:
Steps 8-17:
Steps 18-29:
Step 30-41:
The numbers below refer to the step numbers on the diagnostic table.
2. The A/C compressor relay output is disabled if engine coolant temperature is above 121°C (250°F). The engine coolant indicator will illuminate at this temperature.
3. These actions will enable the A/C compressor to operate.
4. This test ensures that there is sufficient refrigerant in the A/C system. The specific values come from the A/C System Performance Test in Heating, Ventilation and Air Conditioning.
5. The HVAC control module is inoperative when the module does not respond to an operator control request.
6. This action ensures that the powertrain control module (PCM) is getting an A/C request from the HVAC control module.
7. If the A/C request LED does not illuminate the HVAC control assembly is not grounding the A/C request signal circuit.
8. Since the A/C system pressure has been verified in Step 4 this step will verify the integrity of the A/C request signal circuits, if the A/C Request Signal parameter is Yes then there is a concern with the A/C high pressure switch.
10. Since the A/C system pressure has been verified in Step 4 this step will verify the integrity of the A/C low pressure signal circuit and the ground circuit of the A/C low pressure switch, if the A/C Compressor Cycling Switch parameter is Normal then there is a concern with the A/C low pressure switch.
14. If the test lamp remains illuminated the A/C compressor clutch relay control circuit is shorted to ground.
18. If the fused jumper opens during this step the A/C compressor clutch supply village circuit is short to ground.
22. When the blower motor is in the OFF position, a voltage is applied to the OFF blower motor control circuit. The A/C system will not operate if a voltage is applied to the OFF blower motor control circuit.
27. Ensure that both A/C request signal circuits of the A/C high pressure switch are tested for listed conditions.