Mk1 TT Air Con Issue
Discussion
For some reason TT Forum isn't letting me in, no idea why, and I'd like some advice on a MK1 TT225 air con not blowing cold. I've been through a few threads and forums and used their advice to try to trace the issue but not found what I need yet. So, what have I done:
Took it to Kwik-Fit for a re-gas, mainly because it's free if they can't do it; they couldn't and suggested it may be the compressor or control system.
Searched numerous forums and checked the magnetic clutch - not spinning when air con off, spins when air con on - it's fine, or more accurately the clutch is fine.
Check the main fans to make sure they come on when air con switched on - they do
Checked all fuses and relays related to air con, all okay
Checked wiring and stuff, all looks good
Checked the fuses and power lines on the battery fuse box - all good
Blowers work fine, switches between hot air and ambient when in eco mode and temperature dialled up and down - no cold air though
Any ideas on which direction to try next?
Took it to Kwik-Fit for a re-gas, mainly because it's free if they can't do it; they couldn't and suggested it may be the compressor or control system.
Searched numerous forums and checked the magnetic clutch - not spinning when air con off, spins when air con on - it's fine, or more accurately the clutch is fine.
Check the main fans to make sure they come on when air con switched on - they do
Checked all fuses and relays related to air con, all okay
Checked wiring and stuff, all looks good
Checked the fuses and power lines on the battery fuse box - all good
Blowers work fine, switches between hot air and ambient when in eco mode and temperature dialled up and down - no cold air though
Any ideas on which direction to try next?
Kwik fit couldn't do it ? Couldn't do what? Top it up? Are you 100% the gas level is currently correct?
They should add UV dye to aid future leak detection.
Wiring looks good? Looking isn't enough is it, have you tested for voltage, earth etc with a multimeter? 12v at the compressor when the clutch is engaged?
Pressure switch electrically tested and confirmed working correctly?
Is the car selecting cold properly? Ie the flaps in the heater box move correctly?
Could be internal failure of the compressor - any change in high/low side gas pressures when the compressor clutch is engaged to on?
Blocked expansion valve?
Set of AC gauges would be invaluable - watching pressures as you engage the compressor will tell you a lot...
Worth a VCDS scan to see if any issues come up..
They should add UV dye to aid future leak detection.
Wiring looks good? Looking isn't enough is it, have you tested for voltage, earth etc with a multimeter? 12v at the compressor when the clutch is engaged?
Pressure switch electrically tested and confirmed working correctly?
Is the car selecting cold properly? Ie the flaps in the heater box move correctly?
Could be internal failure of the compressor - any change in high/low side gas pressures when the compressor clutch is engaged to on?
Blocked expansion valve?
Set of AC gauges would be invaluable - watching pressures as you engage the compressor will tell you a lot...
Worth a VCDS scan to see if any issues come up..
Edited by DuraAce on Sunday 27th August 10:36
Thanks for the quick replies, there may be some details missing in my original post :-|
Yes, they couldn't re-gas it, there are no leaks but it wouldn't take the gas. No idea if it is full or not.
Flaps move as far as I can tell, without air con it is hard to tell but it does switch between heated air and ambient and all the flaps more around for direction, not sure how to test for cold flap direction, happy to take advice on that.
My understanding was if the switch is knackered, the clutch won't energise, happy to be shown alternative viewpoint.
I don't have air con gauges or the mechanical aptitude to connect pressure gauges to the high/low lines - I'll have to pay for that, trying to avoid doing that blindly so I don't get caught with a replace that, replace this, replace the other - the normal garage/dealer method of tracking down a fault :-|
Wiring is a combination of meter buzzing and visual inspection, as you know, there ain't a lot of room down in the engine bay so probably missed a few. Clutch is engaging, fans are spinning so fair to assume that wiring is okay.
Not sure about the pipes, can't quote get my hands to them near the compressor. If you know of a handy to reach not then let me know.
Happy for more info :-)
Yes, they couldn't re-gas it, there are no leaks but it wouldn't take the gas. No idea if it is full or not.
Flaps move as far as I can tell, without air con it is hard to tell but it does switch between heated air and ambient and all the flaps more around for direction, not sure how to test for cold flap direction, happy to take advice on that.
My understanding was if the switch is knackered, the clutch won't energise, happy to be shown alternative viewpoint.
I don't have air con gauges or the mechanical aptitude to connect pressure gauges to the high/low lines - I'll have to pay for that, trying to avoid doing that blindly so I don't get caught with a replace that, replace this, replace the other - the normal garage/dealer method of tracking down a fault :-|
Wiring is a combination of meter buzzing and visual inspection, as you know, there ain't a lot of room down in the engine bay so probably missed a few. Clutch is engaging, fans are spinning so fair to assume that wiring is okay.
Not sure about the pipes, can't quote get my hands to them near the compressor. If you know of a handy to reach not then let me know.
Happy for more info :-)
Fireblade69 said:
Yes, they couldn't re-gas it, there are no leaks but it wouldn't take the gas. No idea if it is full or not.
If your clutch engages (and stays engaged) then switch etc is probably ok. No guarantees though. How do you know that are no leaks if you don't know the gas level is correct? You can have too much, as well as too little gas.
Why couldn't they put gas in? This is very odd. No reason gas shouldn't go in unless the low side valve is blocked/stuck closed.
With the gas machine connected they should be running the engine + compressor and seeing what happens to high/low side pressures - this will provide excellent fault diagnosis of where to go next.
It's pretty much guesswork otherwise.
Can you feel any cold in any of the pipework?
No idea why, they couldn't elaborate but I assume it is because they can't get it to circulate or something. I may take it to another Kwik Fit and get more information.
The codes on the air con unit show as 0.0 so no malfunction present - obviously there is or it would work so maybe it's something unrelated or all my fielding about has made it work and there isn't any charge in it. I'm having issues getting a full list of checks because the list I have is not matching the car's display so its a bit hard to figure out.
The codes on the air con unit show as 0.0 so no malfunction present - obviously there is or it would work so maybe it's something unrelated or all my fielding about has made it work and there isn't any charge in it. I'm having issues getting a full list of checks because the list I have is not matching the car's display so its a bit hard to figure out.
I would be inclined to let a proper air con garage diagnose the fault, kwik fit seem to have no ability except for gassing the system, anything further and they are out of their depth.
An experienced engineer will probably pinpoint the fault in minutes, may even have come across the same fault before as essentially the same system is fitted to millions of VAG cars.
The guy I used for a Golf knew exactly where the broken cable was and carried spare parts on his van, he repaired it on the driveway, checked it properly and charged less than £100.
An experienced engineer will probably pinpoint the fault in minutes, may even have come across the same fault before as essentially the same system is fitted to millions of VAG cars.
The guy I used for a Golf knew exactly where the broken cable was and carried spare parts on his van, he repaired it on the driveway, checked it properly and charged less than £100.
I would be inclined to let a proper air con garage diagnose the fault, kwik fit seem to have no ability except for gassing the system, anything further and they are out of their depth.
An experienced engineer will probably pinpoint the fault in minutes, may even have come across the same fault before as essentially the same system is fitted to millions of VAG cars.
The guy I used for a Golf knew exactly where the broken cable was and carried spare parts on his van, he repaired it on the driveway, checked it properly and charged less than £100.
An experienced engineer will probably pinpoint the fault in minutes, may even have come across the same fault before as essentially the same system is fitted to millions of VAG cars.
The guy I used for a Golf knew exactly where the broken cable was and carried spare parts on his van, he repaired it on the driveway, checked it properly and charged less than £100.
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