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.
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HOMESERVICE MANUALSBMW1994530I (E34) V8-2997CC 3.0L DOHC (M60)REPAIR AND DIAGNOSISHEATING AND AIR CONDITIONINGDESCRIPTION AND OPERATIONCLIMATE CONTROL SYSTEMS, SYSTEM SPECIFICIHKR2COMPRESSOR CONTROL
1994 BMW 530i (E34) V8-2997cc 3.0L DOHC (M60)
Compressor Control
1994 BMW 530i (E34) V8-2997cc 3.0L DOHC (M60)SECTION Compressor Control
IHKR2 COMPRESSOR CONTROL
- On the 1991 525i, when the A/C system is turned on, the IHKR control module sends the A/C request to the engine control module.
- The pressure switch is in the middle of this circuit. If refrigerant pressure is within limits, the request signal reaches the engine control module.
- The engine control module uses data from its engine control sensors to determine whether to turn on the A/C compressor (by grounding the compressor control relay).
- The engine control module won't turn on the A/C compressor if coolant temperature is too high, or during wide open throttle conditions.
- If evaporator temperature falls too low, the control module stops sending an A/C request signal to the engine control module.
- The engine control module then turns off the A/C compressor clutch.
RENDER: 1.0x
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.