2000 Cherokee A/C

[Sidewinder CC]

according to my a/c guy, my high/low pressure switches are working fine. Its the fact my system is building too much pressure in the first place thats the problem. It shouldnt be climbing to 300+psi at idle.

You should find out what the exact pressures are.

See pressure problems trouble shooting below.

1. Condition:

The low side pressure is normal or slightly high, and the high side pressure is too high.

Possible Causes:

1. Condenser air flow restricted.
2. Inoperative cooling fan.
3. Refrigerant system overcharged.
4. Air in the refrigerant system.
5. Engine overheating.

2. Condition:

The low side pressure is too high, and the high side pressure is too low.

Possible Causes:

1. Accessory drive belt slipping.
2. Fixed orifice tube not installed (unlikely)
3. Faulty compressor.

3. Condition:

The low side pressure is too low, and the high side pressure is too high.

Possible Causes:

1. Restricted refrigerant flow through the refrigerant lines.
2. Restricted refrigerant flow through the fixed orifice tube.
3. Restricted refrigerant flow through the condenser

 

[poppyseed]

Thanks, I think its going to come down to the A/C being overfilled. Im going to take it back to him in the next couple weeks and evac and refill the system. He said the low side checked out at 60 psi, and when hot the high side was at 330psi, thats about when the pressure switch would trigger the a/c clutch to disengage shutting of the compressor. The efan and mechanical fan would then cool the system back down to 200ish psi and the "cycle" would start all over

 

[poppyseed]

I did replace the mechanical fan clutch, and my engine temps are slightly cooler, however the A/C issue is still present.

 

[Redsnake]

Subscribing... I have on/off again issues w/my '01 XJ's AC at times. Always nice to see the what others go through and how to fix these.

 

[Tony_SS]

Subscribing... I have on/off again issues w/my '01 XJ's AC at times. Always nice to see the what others go through and how to fix these.

x2

 

[poppyseed]

I will be taking the jeep in next thursday to evac and refill, will keep you guys posted

 

[poppyseed]

UPDATE: Took the jeep back in and had my A/C guy evac and refill the system. He pulled out 1.68lbs of freon when the system calls for 1.25lbs. So it was definitely over filled.

After he Evac'd it he pulled a vaccuum on it for 20 minutes to turn any possible moisture in the system into vapor and evac that as well. As it turns out there was some moisture in there but not an unusual amount.

After refilling to the proper level we ran the jeep up to operating temperature with the gauges hooked up. We could see the system get up to about 320psi at which point the e-fan would click on and drop the pressure to 220ish psi. It would then slowly climb back to 320 and start the "cycle" over (clutch still constantly engaged).

Eventually the Accumulator would get so cold it would trigger the compressor to click off prior to reaching 320psi. He described this as normalish but acknowledged it cycled more than many vehichles. He believes it to be a Chrysler thing and suggests possibly wiring the efan to be on at all times the A/C is on to help keep the psi down and the system running more consistently.

Overall though, having the system filled to the proper level in addition to what was already done (replace mech fan, pull shim on compressor clutch) has drastically reduced the amount of times the clutch cycles. It cools great now, even when stopped in traffic, but is still annoying to hear it cycle about 4-5 times per minute. (much more than my honda civic or Toyota tacoma)