weird A/C problem

[Atl XJ]

When I get stuck in bad traffic driving home from work, the A/C stops working right before I get home. It start blowing warm air and the compressor stops cycling. After I let it sit for a while it starts working again. Its only done this a few times so far, spaced apart, but I've noticed a pattern to it. Its only been on really hot days like today (95* plus). What would cause this? I'm thinking thats its getting overworked and maybe something is freezing up and after I let it sit for a while it fixes itself. But what would cause that? A malfunctioning part? Low on refridgerant?...

I only live a few blocks from the interstate and both times its quick working after I exited the interstate. That may be a coincidence, that might just be how long it takes to get overworked or something...

'95 XJ 4.0l/AW4.
__________________

 

[anony91xj]

Could be getting hot and the pressure switch cutting it off. Is your electric fan working properly? It should turn on when the A/C compressor kicks on. Open the hood and turn on the A/C while the engine is idling, make sure that fan turns on.

Other than that, have an good shop that does A/C work take a look at it. Unless you've got a good manifold guage set, there's not much you can do yourself.

 

[Atl XJ]

Its not running hot, it hits slightly past 210 occasionally, but not very often. Yes, the electric fan kicks on with the a/c.

 

[jneary]

sounds like the compressor clutch is starting to go out

 

[Atl XJ]

sounds like the compressor clutch is starting to go out

What led you to that conclusion and how can I verify thats what the problem is?

Where is the pressure switch btw?

 

[jneary]

i have seen it plenty of times. when it acts up, check with a test light to see if there is power going to the compressor itself. if so the clutch needs too many amps to pull it and engage the compressor.

 

[Atl XJ]

damn, I was hoping it wasn't something expensive like that.

I havent been on here much in a long time. Arent you one of the guys thats a Jeep mechanic?

 

[jneary]

yeah, i am a jeep tech. i cannot guarantee that is the problem but it is an easy check if you have a test light. i havent been on this site in a while but i decided to check it out again a few days ago.

 

[Atl XJ]

Where is the pressure switch located? I need to check that too.

 

[jneary]

it should be in the accumulator, but if that was bad, the a/c wouldnt work at all.

 

[Dirt]

Man mine was doing the same thing. The compressor locked up last week. I changed the low pres switch. (on accumulator) A few months back just because it's a common problem on Chevy's. No help.

Put the compressor on last Saturday. Runs like a champ now.


BTW... I've got a guy in Conyers that can get you a compressor for the low down. Probably less than 300 for an OEM replacement.

What year is your Jeep by the way?

 

[anony91xj]

Its not running hot, it hits slightly past 210 occasionally, but not very often. Yes, the electric fan kicks on with the a/c.

I'm talking about freon temp/pressure, not engine coolant. With higher temps comes higher pressure, and if the pressure rises beyond "safe" levels the pressure switch will kill the compressor. The fact that this happens consistently when you get off the highway (air stops flowing through the condenser, or flows at a much lower rate) is evidence that this could be the problem.

Was the system recently charged? There could be a little too much freon in there.

 

[dfreeman616]

another simple thing to check is if the condensor is clogged. it looks like a small radiator in front of the coolant radiator. if the air's not flowing through it, then it won't have as much of a temp and pressure drop there like it should, and it could build up pressure and cause it to turn off.

 

[Atl XJ]

Was the system recently charged? There could be a little too much freon in there.

No, its all original. Surprisingly, the A/C still works pretty good--when its working.

 

[xj_mike]

I am having a simular problem. When it it working, it works great! If I keep the fan switch on 3 or 4, the issue with it not working, seems to be less, maybe 3 minutes of not working for every 30-40 minutes working. On the lower settings, it seems to not work more frequently. When this first happened I figured it was the evap as the '00-'01's seem to have problems with pinholes and leaking out. By chance I tried it one day and it was working again, cold no problem. Figured it wasn't the evap but either a sensor, clutch or wiring issue. Luckily it's not a DD so hasn't been a big issue.

Hopefully someone will have a great idea to fix it. BTW, I have a test light, what should I be doing with it, to test the clutch?

 

[Atl XJ]

Can the system being low on refridgerant cause it to be over worked and cause this to happen?

 

[Atl XJ]

I plan on taking the grill out and hitting the condensor with the high pressure wand at the car wash.

So do you have to evacute the system to change out the low pressure switch? By looking at it, it appears that you do.

 

[Atl XJ]

BTW... I've got a guy in Conyers that can get you a compressor for the low down. Probably less than 300 for an OEM replacement.

What year is your Jeep by the way?

Hopefully it won't need one, but I'll let you know if it does.

Its a '95 4.0l/AW4 Country.

 

[Dirt]

So do you have to evacute the system to change out the low pressure switch? By looking at it, it appears that you do.

No you don't. Takes about 30 seconds. Well on my 2k at least.


Give or take.