When mine failed to cool I bought a kit from Adv Auto for $20 that had a can or 134 with dye and stop leak, an ultraviolet light, a can of reg 134 with a gauge. The light showed the leak at the trinary switch which I replaced about 3 years ago and is still cooling well. If you look the system over carefully you could find the leak without the dye. It looks like an oily substance. If it is a major leak from the compressor seal I might spend the $1300 if it is minor I would try the kit first. I try to run the AC even in winter to keep the seals wet.
