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Air Con problems

Psymonkee

Psymonkee

Psymonkee

Soldato
Joined
24 Feb 2004
Posts
14,407
Location
St.Andrews
Hey,

Righto long story but going for the highlights as I want to go play The Walking Dead Ep 3 :p

Mondeo TDCi with rattly DMF + working air con and I took it to my local VW garage to get fixed (know the service guys, got the cheapest quote ~£930 all in). On getting the car back the air con wasn't blowing desperately cold so I returned to the garage.

(Also changing the DMF/Flywheel/Starter has seen an increase of 5mpg!!)

VW checked it over and told me it was out of refrigerant, recharged it and they had it blowing cold. 2 days later it was back to blowing whatever air temperature it was outside.

Took it back again and they did further leak tests on the system, checked over the compressor and found nothing wrong and all the refrigerant is all there.

It's still not blowing cold and their advice is to now take it to a Ford garage for further diagnostic work.

Anyone experienced anything similar and got any helpful pointers? :)
 
Sorry if this is a stupid question, but is the air con clutch actually engaging? You should be able to hear it.
 
Not a clue! Not heard anything from inside the cabin and I sure as hell ain't checking whilst it's lashing it down :p

Had enough showers today already :D
 
Psymonkee said:
Not a clue! Not heard anything from inside the cabin and I sure as hell ain't checking whilst it's lashing it down :p

Had enough showers today already :D
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Haha, well when it's stopped raining, get someone to sit inside the car and hit the A/C switch whilst you listen under the bonnet. It should be a fairly noticeable click/thunk :)
 
Yep can hear that even with the bonnet down whilst toggling the AC on/off myself so I think that's working.

Also the revs rise and fall slightly when it kicks in/goes off so it appears as normal :confused:
 
Psymonkee said:
Yep can hear that even with the bonnet down whilst toggling the AC on/off myself so I think that's working.

Also the revs rise and fall slightly when it kicks in/goes off so it appears as normal :confused:
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When you switch it back on do you hear it click back out after any length of time?

Only real answere is to put a set of gauges on see what the system pressures are doing.
 
Had a similar issue with my Passat, turned out to be a faulty compressor that wasn't turning on properly. On the odd occasion it did actually turn on, it was either a quick on and off, very similar to a system that was low or empty of gas (it wasn't low or empty) or it took 10 minutes to turn on from pressing the button.

Did no end of checks and tests with an indy AC guy (called AC-DC in Derby lol hello law suit), pressure tested, re-gassed, pressure tested again, checked the clutch, checked the relays to see if they were triggering. In the end they pronounced the compressor to be dead. After a replacement it's been working fine :)
 
Could be a multitude of things.

Obvious things to check/test for are:

- Leak?
- Fuses/Relays all ok?
- 12v at Compressor and Clutch?
- Pressure Switch ok?
- A/C button actually working (I.E 12v at compressor)

If its been in for work most obvious thing would be a leak. I'd personally consult an A/C specialist as they will be able to pressure/leak test with Nitrogen and Dye.

If you have a leak the compressor/clutch won't kick in at all as the LP switch should have detected low pressure and stopped it from killing its self.
 
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My dad had a similar problem with his car, turned out there was a leak (split hose) and when the garage did their first leak test they didn't find it...numpties.

Anyway, after spending ages checking everything else over and finding no problems they did another leak test and found the problem.
 
Mobile AC guy has just been and gone and reckons it's the pressure switches that need replaced at £130 - £180 all in (price varies if I need a recharge).

Only thing he couldn't check was the codes for the Air Con system as his laptop is away for repair and only has the old handheld machine. He's suggested if the pressure sensors have flagged a code he couldn't read today resetting them might fix it.

So next question:

Anyone in the Fife area got an OBD2 reader that can read/clear all codes? :)
 
Psymonkee said:
Mobile AC guy has just been and gone and reckons it's the pressure switches that need replaced at £130 - £180 all in (price varies if I need a recharge).

Only thing he couldn't check was the codes for the Air Con system as his laptop is away for repair and only has the old handheld machine. He's suggested if the pressure sensors have flagged a code he couldn't read today resetting them might fix it.

So next question:

Anyone in the Fife area got an OBD2 reader that can read/clear all codes? :)
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Was the pressure okay?
 
Be wary of that. I had similar problems (warm air) and after a regas I had the same warm air after a couple of days. AC guy tested the system and pressure was still there according to the gauges.

Fast forward another day and Laptop was telling me faulty pressure switch, replaced that and when I had the old one out the schrader valve didn't purge out any gas (should release a minuscule amount).

Another pressure test and gas was all gone, hole in the Condenser rad.

Try ECP for a pressure switch.
 
If its a 4 pin switch (fans/compressor) you may be able to bypass the pressure switch and see if you get cold air.

Seems strange though, the switch is there to protect the compressor etc, if that was at fault and activated through a dodgy/bad switch, the compressor shouldn't even be kicking in.
 
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