I had this post in the A/C section for about three days with no response.....since you guys have been more than helpful on my other posts, maybe you could help on this one.

Thanks in advance.

I just recently tried to recharge the A/C on my 96 PSD. The can with the guage that I got from O'Rielly's said to hook it up to the low side, check the pressure then add if needed. I just bought the truck last week and it didn't come with an owners manual. I just need to know which side is the low side. I found two different fittings; one on the left side of the engine when facing the engine up by the black cannister, the other over on the right side of the engine right by the air intake as the line goes in to the condesor. The line by the air intake would not fit the connector that I have and the line up by the cannistor would not take any R134 either with or without the engine running with the A/C on MAX. Any suggestions?

Chris

 

low side = blue fitting(smaller)

 

I don't remember all the spec's for R134A as it's been awhile since I've "done it by the book", but here's a quick primer. Use at your own risk. The hook up next to the reciever/dryer (the canister) is your low side. The blue hose connection will only fit low side. To fill you need to turn on your tuck, trun on the a/c. The compressor, may or may not come on. (Gauges are useless unless the compressor is running.) You may have to turn you can of 134 up side down, or shake it a little to get it go into the system. (When I was "trained" to do retro-fits, it was bad to shake the can, ect. to shoot coolant into the system, as it was thought that it might freeze the pistons in the compressor and cause them to fail. Never seen it happen, but that is what we were told.) Once the system starts taking the coolant the a/c compressor will begin to cycle off and on and suck in more coolant. Off hand I don't know how many .lbs the system holds. When your compressor quits kicking on and then kicking off, your getting close. I want to say you should show around 32-36lbs pressure on the low side when the system is full.