MK5 Golf GTI
All Things Mk5 => Mk5 General Area => Topic started by: alexmckensi on December 08, 2023, 11:20:18 pm
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Started with aircon not working, found it might be something more…
Potential symptoms of problem:
- Aircon doesn’t ever blow cool air
- Radiator fans don’t seem to ever turn on, even if AC is requested (small fan supposed to kick-in here?)
- I don’t hear a ‘click’ when requesting AC from within the cabin
Notes:
- Full scan using OBDeleven, no codes reported
- Refrigerant pressure at 4 bar (no warnings on OBDeleven)
- AC compressor appears to be responding to engine RPM
- All fuses in driver-side port (cabin) and next to engine box are ok (tested with multi-meter)
- Engine temp is relatively quick to get up to 90 and stay there, no overheating concerns although it is winter
- OBDeleven 'Engine Fan 1 control circuit' output test started both fans all good, no problem
Is there any direction / area someone could please point me to in order to continue diagnosing this problem?
Thanks in advance!
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Might sound like a basis question, but is the outside air temp high enough to demand air con to turn on?
eg if the outside temp is 5C and the cabin temp is set to 17C then the system would be *heating* the outside air as it comes into the cabin.
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I posted a similar problem a few weeks ago….
I believe no matter what the ambient temperature, AC only operates when one or both fans are running when the AC signal is sensed by the the fan controller which is housed within the larger of the two fans. I temporarily powered my fan pack from the battery and they both ran at full speed so I’m assuming the controller is fooked. I’ve bought a 2nd hand fan pack off eBay….I’ll report back once fitted.
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Thanks both. A few updates (still no A/C):
- Turns out both radiator fans DO come on when the engine coolant needs it, just not responding to the A/C in any way.
- OBD scan reveals ~0.8A going to compressor (variable).
- Compressor is turning on/off to dash buttons request.
My next line of investigation focuses on the compressor valve + compressor itself.
The compressor appears to be spinning (including the centre).
Would a faulty compressor valve (RCV) cause the small radiator fan to not engage?