**** Ac Unit Only Turns On When Hot Wired ** It Will Blow Cold

[fazd]

I have a 1996 s10 blazer. I charged my ac by hot wireing the unit to get it to come on. It will blow cold when it is on, but it only comes on if I run a direct wire from the pump to the battery. I had a thunderbird that was the same way. Is it because I am not charging it correct?

[nukmanz]

I'm no expert on this matter but I recently had A/C problems on my 92 Silverado. After having my system converted from r-12 to r-134, the A/C would work briefly, then give me an A/C failure on the control panel (A/C light would flash).

I reset the light by disconnecting the negative terminal on the battery for a few minutes and it would work fine for a short period then fail again. The problem ended up being the pressure switch that fits into the dryer (located near the firewall, where the high pressure and return lines enter the firewall). It turns out that the switch for r-12 is diferent than the one for r-134. The mechanic said that sometimes the switch can be adjusted to correct the problem but I had him replace it anyway.

The correct charge level is critical also and could be causing the problem. The only way I know to determine that is to have it hooked up to gauges by a qualified mechanic.

Hope I have been some help. Good luck and stay cool