What are the symptoms of Air conditioning stopped cooling / no response to AC button in BMW 118i?

No cold air from vents. Clicking or rattling behind dashboard. Frost or ice on pipes under the hood

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Air conditioning stopped cooling / no response to AC button

Q: How to fix Air conditioning stopped cooling / no response to AC button in BMW 118i?

Diagnostic procedure before replacing the compressor: (1) Check the fuses and relay of the AC compressor. (2) Check the operation of the electric radiator fan - with the air conditioning on and the engine running slowly, the fan MUST work. (3) Perform a pressure test with manometers - the static pressure of the system at 20°C should be approx. 5-6 bar. Too low = leakage. (4) Observe the compressor pulley: the outer ring always rotates (belt drive). The middle clutch plate should engage when the AC is turned on. If not, power the coil directly (+12V) and observe. Clicking = electrical problem, no clicking = damaged clutch or jammed compressor. Quick fan test: turn off the AC, start the engine, turn on MAXIMUM AC (max cold + recirculation). Watch the electric fan behind the radiator - after 10-15 seconds it should run at full speed. If not, that's why the air conditioning doesn't cool, not the compressor.

in BMW 118i (2004-2013)

Symptoms

No cold air from vents
Clicking or rattling behind dashboard
Frost or ice on pipes under the hood

DTC error codes

AC Compressor Clutch - no control signal

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Technical diagnosis (Premium)

Recognized technical fault:

Auxiliary controller voltage instability detected

Technical analysis

Detailed analysis of HVAC controller operation parameters, CAN bus data readings, and diagnostic signal waveforms. Purchase PRO access or log in to read the full fault analysis.

Confirmed solution

Complete step-by-step repair procedure including module non-volatile memory reset, sensor calibration, and correct wiring routing. Unlock the full report to see the instruction.

Parts needed

Filters ferrite anti-interference / noise suppressor
Auxiliary starting battery (depending on cell status)

Workshop hacks

Important workshop tips for mechanics regarding bypasses without expensive control module replacement and manufacturer software service bulletins.

TSB / TPI service bulletins

TSB-24-HVAC-01TPI-2068943/2

A/C Technical Specifications

Refrigerant specifications for this model are available in the catalog.

Open refrigerant database

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