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.
Chart C-10 - A/C Clutch Control CKT (1 Of 2)(3.4L "W" Body): Notes
A/C clutch control relay is ECM controlled to delay A/C clutch engagement about .4 second after A/C is turned on. This allows IAC to adjust engine RPM before clutch engages. ECM also disengages A/C clutch during WOT, when high power steering pressure is present, or if engine is overheating. The A/C clutch control relay is energized when ECM provides a ground path for circuit No. 459. The A/C pressure sensor is used to determine high and low pressure in system and also turns on cooling fan when needed.
- ECM will only energize A/C relay when engine is running. This test determines if relay or circuit No. 459 is faulty.
- This test determines if signal is reaching ECM on circuit No. 66 from A/C control panel. Signal should only be present when A/C or defrost mode has been selected.
- If ECM see a high power steering pressure signal, ECM will disengage A/C clutch.
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.