I took the car into to get the AC recharged and the mechanic says that the compressor is seized, To get the system running properly again he quoted me 1600, but 600 or so was just the compressor. He also told me that my ambient temp sensor and housing was completely missing, anyone ever heard of that happening?

 

You can get a nice used compressor in the MKIV classifieds on vwvortex.com. Most will cost you about $50-150. The $600 if for a rebuilt one and a new one is another few hundred.

As for the sensor, the previous owner could of wrecked the car or removed it for a fmic, not sure. Not going to hurt anything unless you really want to have one.

 

The wires for the ambient temp sensor are in the same harness as the horns you could start there and see if a previous owner relocated it or just cut it out