# air con not working



## andyq (Jun 12, 2010)

my air con is not working and i'm sure its because the compressor is not engaging. i've done a quick search and someone mentioned fuses, where are they so i can check ? Also where is the magnetic clutch and how do i access it (from above or below), is this an easy DIY replacement and at what cost.
thanks
andrew


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## HIRAM (Feb 15, 2010)

viewtopic.php?f=2&t=263722


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## andyq (Jun 12, 2010)

thanks for that buts its not helped. can anyone tell me how to access the magnetic clutch and test it?


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## HIRAM (Feb 15, 2010)

First locate F129 pressure switch this is on the left hand-side of the engine bay as illustrated below as per Bentley workshop manual, on earlier TT's its on the bulk head on the left it may or may not be covered with a "Silver Foil Sleeve" with "poppers"

You will require a piece of wire to "bridge" or "jump" the terminals as below

Remove the wire loom connection

connecting terminals 1 & 2 should activate the electromagnetic clutch as per illustration below

connecting terminals 3 & 4 should activate the fans as per illustration below

the "A" is the pressure switch

If the pressure switch is faulty ie stuck in the "OFF" position the clutch and the fans will not operate,but if you jump them with the terminal "B" connection they will work

If the "activator" which the switch screws into is defective it wont work either......

You can "safely" unscrew the "A" pressure switch without depressurization of the air con system but if it's faulty you will lose your R134a coolant

You should get a VCDS / VAGCOM check done

Rob

HOW TO RECHARGE THE R134a

http://www.youtube.com/watch?v=B_XkaAHv ... ure=fvwrel


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## jaqcom (Apr 20, 2009)

If its not the obvious.............mine failed last year (V6) and it was the main metal/rubber hose that had chaffed and leaked gas,............. it was expensive (£500) as Audi had to remove front end face to access and pipe was £120.
If you search I did post it ...........good luck hope its a fuse LOL 8)


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## andyq (Jun 12, 2010)

right i've had time to investigate. air con and clutch are fine. found that fuse S164 (on top of where the battery would be on a 225, this is a QS) had blown. everything worked fine yesterday air con blew cold, radiator fans kicked in and the electric after run pump whirred away after stopping. took it for a good long this morning and the fuse blew again. its either the the cooling fans that are seizing (rotate nice and freely though) or the after run pump that is borderline seizing or the clutch is shorting. going for a run now and i'm not going to use the air con. if it still blows the fuse i'll disconnect the after run pump then that can only leave the radiator fans. after that i'm stumped, anyone know a good auto electrician in Huddersfield. totally spoiling my weekend this. [smiley=bigcry.gif] [smiley=bigcry.gif]


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## andyq (Jun 12, 2010)

did a run yesterday and everything worked ok. when i left the car in the garage the fuse was intact and the after run pump was running. checked this morning and the fuse had blown, tried putting another fuse in and it immediately sparked so i pulled it out. there is a -12v permenant voltage across the fuse terminals. disconnected the after run pump and it was still there. suspecting the fan control module, desparatley need help without this fuse the cooling fan and the after run pump won't work.


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## andyq (Jun 12, 2010)

decided to give in and get professional help, took the car to Autolec in huddersfield. they found a short in the wiring under the battery tray, the wires had chaffed. glad to get it sorted but my faith in this car has been shaken. compared to my previous steed a 306 gti its unreliable.


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## HIRAM (Feb 15, 2010)

Glad you got there in the end, here's a photo of my TT with wiring /air con problems  [smiley=book2.gif] :?


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## Esoxlucios (Aug 20, 2013)

andyq said:


> decided to give in and get professional help, took the car to Autolec in huddersfield. they found a short in the wiring under the battery tray, the wires had chaffed. glad to get it sorted but my faith in this car has been shaken. compared to my previous steed a 306 gti its unreliable.


Regarding that problem you had 18 months ago: how were the wires chaffed? We're they rubbing against the metal somewhere, or cut by the fan blade, or just get worn out inside the harness from vibration and movement?

I'm having the same problem after replacing the horn, which required me to move that part of the harness around a bit. Now, I need to locate the short.


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