Ok, first I'll say that the Blazer was neglected for 2 years, sitting outside, rotting, but (If you didn't read my 4x4 post) I went over to the house where it's been staying, and changed the battery and oil, and it fired right up! No hic-ups, coughs, or anything... It runs perfect (actually I think better than when I parked it). BUT, the A/C did work when I parked it. I converted the A/C from R-12 to R-134a before I parked the car. I just assumed that it needed topped off, so I went to wal-mart, grabbed me a couple cans, and went to top it off. Well, when I hooked the hose up to the condensor, it read in the normal levels... ??? So I looked a little harder, and I noticed the compressor never engages... Doesn't even try. So, not knowing the first thing about the schematic of how the A/C works on the blazer, I took the connector off of the compressor (2-wires) and tried to get a voltage reading out of them, but I got Zero accross the board with the A/C on. What should I look at now? It was 99 today, and I was seriously contemplating removing all 4 doors and back glass (as I'm basically going to turn the Blazer into a 4x4 toy anyways), but I still would like some A/C. Any ideas???

lol, here's a clip of me starting the truck after 2 years, I wanted to document if it blew up, but it surprised me and fired right up:
http://bcwhite.net/movies/starting_up.wmv

 

On the same canister where the low pressure hose connects for charging there is a transducer that monitores the freon charge. Disconnect the transducer wires and jump across them. This should engage the compressor.

 

So let's ***-u-me that I jump the wires, and the compressor engages, this would mean this trnsducer is bad?? If so, how hard of a job is it to swap out?? I would just go look, but I was called out of town for work today, and won't be able to work on the Blazer until tomorrow...

 

In order to charge an a/c system, you need the compressor to be running. Even checking the low side pressure must be done with the compressor running. It'll always read higher when the compressor isn't running. So... Your transducer could still be good and it could still just be low on refridgerant.

 

I have the same problem. I know where the low side is. What does the transducer look like?

 

Tks guys, was my transducer. Changed it out, re-charg, and all good