To make a very long story short, after copius amounts of research I converted my truck to an electric fan setup out of a Town Car. The idea was to wire the system with two relays, a 75 amp unit that controled the fan off a temperature switch, and a 30 amp that caused the 75 amp unit to connect when the A/C came on. Looked good in theory...had the right plan...installed it all exactly to the plan...and it turned out the 75 amp relay I ended up with was quirky and the 85/86 pins were opposite of a normal relay. I figured that out eventually, and everything works like a charm now, but before I did, I think I overpressured the A/C compressor by feeding power into it instead of getting trigger power for the 30 amp relay. I was in the cab when it went off. It sounded like something blew up, and there was refrigererant everywhere under the hood. I saw enough of what happened to know it came from somewhere on the top of the compresor. I couldn't see any visible damage, so I figured it blew a seal. After I bled off the rest of the pressure, I replaced all the seals, and found none to be damaged. But one other thing I did find was what apprears to be a pressure relief valve on the top of the compressor. It's actually on one of the hose assemblies and protudes from the bracket where the hose bolts on. So, two questions...first, is this really a pressure valve? And two, if it does release pressure, is there any permanent damage to it or the compressor? I can't find it documented anywhere in the reference material I have.