What are the symptoms of Blower vents emit warm air when A/C is turned on in Volvo 850?

No cold air from vents. Problem visible at standstill or in traffic. Problem appears while driving. Air conditioning works intermittently

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Blower vents emit warm air when A/C is turned on

Q: How to fix Blower vents emit warm air when A/C is turned on in Volvo 850?

Performing the so-called procedure 'shim fix' - dismantling the compressor pressure disc (often without unsealing the system and removing the compressor) and removing spacers (shims) from the axle to restore the factory clearance of 0.3-0.5 mm. An alternative, temporary method of repair is to insert cable ties or e-clips under the rubber shock absorbers of the front clutch in order to mechanically reduce the gap.

in Volvo 850 (1997-2021)

Symptoms

No cold air from vents
Problem visible at standstill or in traffic
Problem appears while driving
Air conditioning works intermittently

DTC error codes

No faults in controller

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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

Standard

Refrigerant: R134a Amount (g): 750 – 825g Oil: PAG PAO 68 lub PAG ISO 46 Oil (ml): 200ml

See full specification

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