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CATOMITE
13-03-2008, 09:58 PM
Hi, I Have A 1996 Passat Tdi Varian (66kw), The Air Con Doesnt Work Ive Bypassed The Switch And There Is No Voltage At The Compressor Neither Does The Radiator Fan Kick In, Can Some Body Please Help Me On This. Could It Be The Relay? (what Number Is This?) Ive Checked The Fuse And Thats Ok, Ive Goto Change The Switch (there Is Voltage At The Switch. Please Help Chaps And Chapesses
Thankyou

erico
25-04-2008, 12:05 PM
Hi, I Have A 1996 Passat Tdi Varian (66kw), The Air Con Doesnt Work Ive Bypassed The Switch And There Is No Voltage At The Compressor Neither Does The Radiator Fan Kick In, Can Some Body Please Help Me On This. Could It Be The Relay? (what Number Is This?) Ive Checked The Fuse And Thats Ok, Ive Goto Change The Switch (there Is Voltage At The Switch. Please Help Chaps And Chapesses
Thankyou

If there is not enough of a refrigerant/oil charge the compressor will not work. you can check the compressor clutch operation with direct 12v to the connector on the compressor. If if jumps slightly with a click sound then it is likely to be OK. The radiator fan will not kick to high speed if the air conditioning is not operating.

Send me a PM with you email address and I can send you the schematic in PDF format from the Bentley manual. You could very well have a dead compressor as well.
cheers,
Eric

Mike 8-{>
26-06-2010, 12:22 PM
I hope raising an old thread isn't poor form. If it is then my apologies.

It sounds like I may have a similar problem. I have a 96 passat estate 1.8 petrol CL. The air con has stopped working. There seems to be no voltage at the compressor to pull in the clutch. The clutch assembly spins freely. The fuse board hasnt got any blown fuses. I'll try the suggestion of applying 12v direct to the clutch solenoid wires (the pair of red wires running along the top of the compressor to a connector at it's far end?) At the moment I only have a Haynes manual to go on and it seems a tad light on info on the Aircon side of things.

As I am a newbie and don't have enough posts yet I'm not yet able to pm you to ask for a copy of the schematic you generously offered to the earlier poster.

Any thoughts comments welcome.

Thanks

Mike 8-{>

erico
26-06-2010, 01:19 PM
if there is not enough freon under pressure, a low pressure switch will prevent the compressor from operating. That is a safety interlock circuit to protect the compressor by design. There is also a high pressure switch on the high pressure side to provide safety as well.

You can put 12v from a separate source to verify the clutch is good, but that probably won't solve the issue.

I suggest that you have your system evacuated and recharged at a licensed shop. Where I live (the Netherlands) it costs @ €150,00 to have that done. The receiver drier will probably also need replacement as they fail when the freon too much moisture has entered the closed system .

The Haynes manual is light on AC info because air condition refrigeration/cooling circuits have inherent dangers.
If you make the grave error of trying to put a charge of refrigerant or evacuate the system on the high side instead of the low side of the compressor you could cause yourself a big and perhaps life threatening problem. Knowledge of the system and laws regarding disposal of used freon require licensing to legally work on air conditioning systems.

Mike 8-{>
26-06-2010, 01:27 PM
Hi Eric, thanks for the speedy response :)

I understand what you are saying regarding the refrigerant. I dont think this should be a problem. I had that side of things serviced last year.

I'll have to see if I can find some more detail on the pressure transducers you have mentioned.

Cheers Mike 8-{>