AC won't always engage

'05 Passat AC won't always engage and start cooling. Might work for a week and then stop working for a week. I have searched and read the numerous threads on this issue and wanted to start a new one.

If the compressor does engage, it cools nicely. Problem is getting it to engage. The radiator aux fan always comes on, but the compressor doesn't.

Have pulled the 384 relay and checked it. It does "click" every time and the contacts are actually changing state when I ohm them out. It is also tight in the socket. Doesn't seem like this is the problem.

Some of the other htreads comments on the pressure switch not working right. I would check the (Hi/Lo??) pressure switch contacts if I could find it. Anyone know where it is located?

I do have maintenance insurance through an outside vendor that I can fall back on to get this fixed, but there is a $100 deductable and I like fixing things myself (I am also cheap).

Is the Bentley manual the only way to view the electrical schematic for the AC?

Any help is appreciated!

I had this issue as well, and I went to a salvage yard to find a used relay. The guy let me plug it in to see if my problem went away, and sure enough, it did. My existing relay also clicked, but for some reason the AC didn't engage. I'm pretty sure that the relay is bad, and that a new one will take care of it. Problem is, the dealer won't let you "try before you buy", so try the salvage yard. The relay is common to a number of cars, so they need not have a TDI on the lot.

I'd stick a new relay in there. They will click, but will still not complete the circuit for some reason.

When I first ohm'd out the relay contacts, they were not "solid". I burnished them clean and got them working good. However, I did not have a pinout of the relay and did not check every pin. I'll see about getting a new or used relay.

Thanks!