Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Regulating The Air Conditioning (A/C) Compressor
The air conditioning (A/C) compressor is controlled by the engine control module (ECM) (4/46) on request from the climate control module (CCM) (3/112) via the controller area network (CAN). When the engine control module (ECM) receives a signal from the climate control module (CCM) to activate the air conditioning (A/C) compressor, the engine control module (ECM) grounds the circuit for the relay coil for the A/C compressor. See also: AIR CONDITIONING (A/C) RELAY
The relay (2/22) closes the circuit between the integrated relay/fuse box in the engine compartment and the clutch for the A/C compressor (8/3).
In addition to the information from the climate control module (CCM), the engine control module (ECM) checks the engagement and disengagement of the A/C compressor based on:
- the signal from the air conditioning (A/C) pressure sensor (high pressure side) (7/8)
- the signal from the air conditioning (A/C) pressure sensor (low pressure side) (8/119)
- the throttle position (TP) sensor (6/120)
- the engine coolant temperature (ECT) sensor (7/16).
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.