A/C Compressor/Clutch Problems

[Slykin]

First off, for the very few people that recognize me.. i'm back.. It's been years since I've been on here or been in the mustang scene. But anyhow, on to the A/C problem.

I recently charged my A/C because it was low and blowing hot air. After charging, it was blowing frigid cold air. Awesome. It's finally fixed and working. The problem occurs the very afternoon I charged it.. that very evening(a couple hours later) I went to drive to the grocery store and the A/C was blowing straight up hot air. I automatically figured that it had a massive leak and I just needed to change o rings and recharge.

Well, the next day I drove to work and it was blowing ice cold air again. Got done with work expecting the A/C to be working... but it started blowing hot air again after about 10min of cold air. Decided to check the freon levels again but the A/C clutch won't engage. I tried jumping the low pressure switch and the A/C clutch won't spin. Needless to say, i'm confused. It appears that my fuses are fine too, but I have no idea if the CCRM is good/bad or if I should even check that first.

CHECKLIST:
Jumping low pressure switch doesn't work
Low Side Pressure with compressor off: 110PSI(90F Ambient temp)
High Side Pressure with compressor off: 100PSI(90F Ambient temp)
Fuses Good
Blows Cold in the morning for one 35min drive and gets hot after 10min of driving in afternoon

Any help would be appreciated.

 

[lwarrior1016]

Have you changed any parts in the system? Check the air gap on the clutch, or pulled the orifice tube and inspected? When the clutch isn't engaged but everything is turned on, check the plug at the compressor. You should have 12v there and good ground on the other pin.

 

[Slykin]

The only parts changed were the accumulator and service ports. I had old teflon-ball valve ports that were leaking so I dumped the system, vacuumed it, and put it all back together with the new accumulator. I haven't pulled anything else since then.. trying to avoid that if possible but will if needed. I really really really should have replaced the orifice tube when replacing the ports, but that was almost a year ago and I wasn't as knowledgeable about things then.

I'll check the voltage tomorrow... i'm hoping it's just a loose connection of some sort.

Also, I took it out for a spin again this evening and it cooled for maybe 20sec and then went hot on me again.

 

[lwarrior1016]

When it starts blowing hot, the compressor isnt engaged, right?

 

[Slykin]

Correct

 

[lwarrior1016]

Correct

Ok, so if we look at high and low side pressures with the low side switch jumped thatll tell us if the system is charged enough to keep the compressor engaged. If it still isnt engaged we could be looking at a bad high side switch or a ccrm problem. I would run it until the compressor kicks off and then disconnect the compressor connector and check voltage.

 

[Slykin]

My compressor won't jump using the low pressure switch, so that's why I'm thinking its the compressor/clutch or electrical. Hoping it's not the compressor since it was blowing super cold the day before.

 

[lwarrior1016]

My compressor won't jump using the low pressure switch, so that's why I'm thinking its the compressor/clutch or electrical. Hoping it's not the compressor since it was blowing super cold the day before.

Thats a good possibility, thats why I would like to see what the voltage is, at the compressor, with the switch jumped.

Oh, did you ever get to check the air gap on the compressor clutch?

 

[SnakeBit!]

is your radiator fan coming on when the a/c is switched on?

 

[Slykin]

Ok, so I checked voltage on the compressor with the AC on and got 13.96V. I'm going to assume that this means either my compressor or clutch is bad. As for air gap.. don't know what that is or how to check it. And yeah snakebit, it comes on.

 

[Slykin]

It did make one quick rotation right when I plugged in the power. Not sure what that means if anything.

 

[lwarrior1016]

It did make one quick rotation right when I plugged in the power. Not sure what that means if anything.

When you plugged it in, the clutch engaged and rotated once then disengaged, right? Can you rotate the compressor by hand?

 

[lwarrior1016]

Ok, so I checked voltage on the compressor with the AC on and got 13.96V. I'm going to assume that this means either my compressor or clutch is bad. As for air gap.. don't know what that is or how to check it. And yeah snakebit, it comes on.

Looking at the compressor front, the clutch part that moves in when you turn it on, between that and the pulley there is a gap. That is the air gap. Its basically how far the clutch has to travel toward the pulley to engage. Since yours is kicking on and then going off, I dont think that is your issue.

 

[lwarrior1016]

Do you have a set of manifold gauges that you can check high and low pressure when the compressor does run?

 

[Slykin]

I have gauges, but I can't get the compressor to run at all. It spun for literally one rotation when I plugged power back into it, but that's it.

 

[lwarrior1016]

I have gauges, but I can't get the compressor to run at all. It spun for literally one rotation when I plugged power back into it, but that's it.

Kind of sounds like the clutch is bad but getting a replacement clutch and getting it installed with the compressor in the car becomes a problem. You would be better off replacing the compressor with a new one that comes with a clutch.