Air conditioning help please.

lshobie

 
Joined
Feb 1, 2004
Messages
3,046
Hi Guys/Gals,

Just trying to get my a/c up and running on my 89 BJ74. The system has pressure, the compressor turns, belt is tight, i can hear teh relay click under the dash, teh fuse is good, but the compressor doesnt seem to kick in - low pressure cut in switch?

ANy suggestions or experience with these things?

Thanks

Louis
 
Joined
Jan 20, 2003
Messages
11,195
Location
Wherever the truck stops!!
Is the fan on?? The fan must be on (it probably is if the relay is clicking) or the system doesn't work. There is a low pressure switch but it's in the evaporator box on the '60 (not sure on the '74 series) making getting to it a pain in the butt.

The other, more likely, possiblity is a bad fan clutch and/or incorrect spacing on the fan clutch.
 

Stone

Moderator
 
Joined
May 13, 2004
Messages
3,130
Location
BC, Canada
Did your problem just come up suddenly, and didn't worsen over time?

Mine just started blowing warm air one day, and with a little bit of help, found that the problem was the stator coil in my AC compressor. The FSM goes through the diagnostics of this, but basically, there is one lead coming from the compressor (black wire with a plug), and this wire should see a specific number of ohms to ground. Mine was infinity, so the stator coil wasn't engaging the magnetic clutch to turn the compressor. An easy way to see this is to have your engine idle, turn on your AC, and see if the pulley on the compressor starts to turn.

More on this thread:
https://forum.ih8mud.com/showthread.php?t=41234
 

lshobie

 
Joined
Feb 1, 2004
Messages
3,046
Excellent info - thanks guys. I'll get at it tomorrow.

I am working on a truck I just brought in, it is a decent rig, but needs some fine tuning.

Regards
 

lshobie

 
Joined
Feb 1, 2004
Messages
3,046
HI Guys,

I put power to the compressor and the clutch engaged - so it's good and there is no power to teh compressor.. I then looked at the VSV and it had a hose off it and the idle up hose was attached to the wrong pipe, so I fixed those. Then I checked the pressure switch - it is blown from what the multimeter tells me.

So, are pressure switches available at the dealer? anyone have a part number? Any suggestions?

Regards
 
Top Bottom