I don't remember anymore, but did you replace the pressure sensor on the evaporator tube? It should have a Schrader valve behind it, eliminating the need to recover the system beforehand. Yes that was one of the first things I did. I finally fixed it. Well I took it to a mechanic who tested everyth...

ok yeah, I thought about that as well, but when jumping it there is no problem to jump the power. I even tried taking the fuse block off to get to the wiring connectors but it was getting a little tricky so I stopped. However, as I said, the terminals jump no problem. Who said that troubleshooting ...

When I jump the relay the compressor kicks on so the wiring should be fine between the relay and clutch. But I checked anyway for continuity on the wire between the relay terminal that feeds the compressor clutch and it read 1.4 ohms. Then something has to be amiss in the area of the relay...maybe ...

Okay...we've got the system charged to specs. It could also be the wiring from the relay to the clutch, the diode that prevents stray voltage induced from the clutch coil from traveling back to sensitive electronics, or the PCM itself. Try the easy test first. Put a VOM's test leads across the wire...

My first inclination is to recover/evacuate/recharge to get the correct amount of refrigerant into the system, and then see if the compressor runs normally. Even though the compressor engages when you jump it and the system blows cold, it could still be low on charge. The specifications that I have...

I will try that John. Thank you very much.

Hi John. Thanks for the reply. I did hook up a manifold and had about 85 psi IIRC. When I start the engine and press the ac button and the clutch doesn't engage I jumped it and it was working fine with ice cold air. Low pressure was 35-40 psi and high was I think around 130-150psi but it's been a co...

I have a 1999 GMC Sonoma 2.2. I've attached the wiring diagram for your reference. Before I delve into it let me first state that my compressor clutch kicks in when jumping terminal and when jumping the relay terminal. I've also switched relays with the horn relay (it's good) and nothing My pressure...

Ok, so the hand wheels at the end of the hoses open and close along with depress the valve on the ac ports on the ac lines. That makes sense. Thanks Johnhere.

all these videos on Youtube show that after pulling vacuum and then closing the valves at the manifold to see if the system holds a vacuum. However, wouldn't this just close the manifold? I pulled vacuum and then closed the valve at the manifold on both high and low side and left it to sit for 2 day...