Cooling season is on again off again and soon to be on for an extended period. The A/C on my '05 sable has decided to take the summer off. I dumped in two cans of R-134 about two weeks ago and it worked for a few days and has now gone back to non functional. I can by pass the pressure switch and make the compressor work, but as soon as you take the by pass out it quits. Must have a leak somewhere, but nothing obvious. Anyone got a "usual" trouble spot to look for? The car has 132k on it.