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Fogging the windows from the inside and errors / Flashing air conditioning pa...

Q: What are the symptoms of Fogging the windows from the inside and errors / Flashing air conditioning pa... in BMW E64)?

Fogging windows. A/C does not react to control panel settings

Q: How to fix Fogging the windows from the inside and errors / Flashing air conditioning pa... in BMW E64)?

For error 9C54, the AUC sensor under the hood must be completely replaced. In the case of the misting sensor (9C55), repair involves gluing it with new silicone gel and pressing it precisely with a force of at least 15 N/cm2 (strong pressure with the thumb). A common problem in older models, especially after improper windshield replacement.

in BMW E64) (2003-2010)

Symptoms

Fogging windows
A/C does not react to control panel settings

DTC error codes

9C54

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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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