A/C compressor not coming on.

[h0tr0d]

Hey guys, we're up to 80 degrees here in Texas and my air conditioner stopped working over the winter and I need it to start working fast since I haul my kiddo around in it.

So far, I've checked the pressure, and it was a tad low, but it still had some. I jumped the low pressure switch (I think it's on the aluminum canister by the passenger side firewall) to no avail. I ran two wires to the battery to test the compressor clutch and it does engage the clutch when 12v is applied, yet it still doesn't seem to be cooling.

What else should I try? I'm fairly new to troubleshooting a/c systems. Do you think it could be the A/C relay?

Any help is appreciated,
-Pat

 

[retorq]

You said you checked it and it was low, did you fill it up?? Perhaps it's a blocked filter??

 

[h0tr0d]

I had the can connected to it and it filled it from about 1/4 on the blue scale to nearly touching the red before I disconnected it. Which filter are you referring to?

 

[retorq]

It's along skinny thing that goes in one of the hoses. I'm no AC expert, mine was filled with gunk when I first got the truck, a local shop fixed it.

 

[h0tr0d]

I'm not sure I'm prepared to de-pressurize the system just yet before checking some other options. On another note, I checked the relay and it tested good. The 10A fuse in the relay box for the A/C is good as well.

 

[bowtiefreak]

was the needle spiking when you went to fill it up? The needle needs to remain still. Try hooking the can back up and rocking the can as the direction say. set the AC to full and let the stuff flow in, the compressor shold start coming on. Once the needles stabilizes you are good.

I had the same thing happen to me and it was driving me nuts

 

[SunlitComet]

Low pressure cut-out switch is on the top of compressor on line manifold mating block just in front of the service port. The high pressure cut-out switch is on the back of compressor. It looks like you were messing with the cycling switch. check the low cutoff switch jumpered with a/c commanded on from the in dash headand see if it activates. if so your level may still be to low.

 

[h0tr0d]

bowtiefreak: I'll have to try again tomorrow when I pick up a kit that has some kind of trigger or control valve for the r134a. The one I had was old but the can was new and I popped it off of there before it got to the red zone.

sunlitcomet: That was what I was thinking it was. It was actually the first one that I jumped across and it didn't do anything when I did that which lead me to believe the problem lies somewhere else other than the pressure in the system. Theoretically if everything was working as it should, when I jumped those pins it should have kicked the compressor into action even if the pressure was too low. (I got the bad info about where the switch was in an old post about air conditioning although in my Haynes it does show it there on the older trucks.)

 

[AtomicHoe094]

the filter is called an orifice tube if your wondering

 

[h0tr0d]

Well, I was able to fix it. I just had to ignore the warnings on the can and let the pressure rise WAY into the red danger zone and then the compressor kicked in and it dropped down to ~20 PSI. Thank god it's fixed....it's getting really hot down here already.