Air Conditioner Troubles

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

desertkj

Full Access Member
Joined
Jan 30, 2006
Messages
3,735
Reaction score
6
Location
Arizona
Ok, I am a bit confused with my Jeep right now. Now that it has started to warm up here in AZ, it has been necessary to crank up the ac again. However, it will run ice cold for about 10 minutes, then the air is at least as warm as the ambient air temperature for about 5 minutes, then it goes cold again. It is a constant cycle that has been occurring everytime I use it. It just had the refrigerant filled and a discharge line repaired in an attempt to solve the problem. What could be causing this?
 

Corwyyn

Full Access Member
Joined
Feb 5, 2005
Messages
2,524
Reaction score
7
Location
Southeast of disorder...
I'm not a great A/C tech but my guesses would be either A) one of the pressure switches (high or low side) may be going out, or B) possibly some air in the system? Hopefully someone will chime in with a better answer, I need to learn more about the A/C stuff.
 

sleeve

Full Access Member
Joined
Oct 28, 2008
Messages
393
Reaction score
3
Location
Woodward Ave
Sounds like you are loosing pressure in the system as soon as the compressor disengages which then doesn't allow the two other major components (condensor & evaporater) to do their jobs.

Did you have a leak test done?

Does the system hold pressure?
 

tjkj2002

Full Access Member
Joined
Dec 17, 2006
Messages
10,612
Reaction score
41
Location
Somewhere between being sane and insane!
If you have a leak in the A/C system it would not blow cold,then warn,then back to cold.I'd be looking at at the temp sensor near the evaporator or a possible compressor starting to fail and/or clutch.
 

desertkj

Full Access Member
Joined
Jan 30, 2006
Messages
3,735
Reaction score
6
Location
Arizona
If you have a leak in the A/C system it would not blow cold,then warn,then back to cold.I'd be looking at at the temp sensor near the evaporator or a possible compressor starting to fail and/or clutch.

That's what I've been hearing. 2003KJ also suggested that it could simply be overfilled and causing the Hi/Lo pressure valves which Corwyyn mentioned to be tripping. It's going in tomorrow. I would have a friend help me fix it, but we've already given money to the dealership weeks ago to fix it, so we are going to make them do it. I wanted to get potential causes before I took it in to make sure I did not get taken for a ride though. I'll also post up what the cause was for future reference.
 

desertkj

Full Access Member
Joined
Jan 30, 2006
Messages
3,735
Reaction score
6
Location
Arizona
Well, dealership had it overnight. Replaced a "fan clutch", said it was fixed, and the problem continues, so back it goes, and it's getting unfriendly......
 

HoosierJeeper

Gold Supporter/Admin
Staff member
Administrator
Joined
Jan 20, 2009
Messages
20,874
Reaction score
299
Location
Western WI
Well, dealership had it overnight. Replaced a "fan clutch", said it was fixed, and the problem continues, so back it goes, and it's getting unfriendly......

Hate when the stealership does't do the job right..or any shop for that matter. Good Luck, keep us posted.:)
 

Dave

Administrator
KJ Supporting Member
KK Supporting Member
Joined
Feb 22, 2006
Messages
15,567
Reaction score
15
Location
on here
Desert.......They should be able to diagnose that thing......especially where you are in the desert.......geeezzzzz. They must do a/c stuff there all year since no one there can live without it. You would think they should be real good at a/c systems in Az for cryin-out-loud.

The most common thing would be a refrigerant leak (that r-12 stuff). They should recharge the system and put a dye in the system and then check it with a black-lite pen or whatever you call those things for leaks. If not that then the temp switch that turns the compressor on and off might be bad. That is about all I know about a/c systems, except I have recharged them myself.

Dave
 

desertkj

Full Access Member
Joined
Jan 30, 2006
Messages
3,735
Reaction score
6
Location
Arizona
Desert.......They should be able to diagnose that thing......especially where you are in the desert.......geeezzzzz. They must do a/c stuff there all year since no one there can live without it. You would think they should be real good at a/c systems in Az for cryin-out-loud.

The most common thing would be a refrigerant leak (that r-12 stuff). They should recharge the system and put a dye in the system and then check it with a black-lite pen or whatever you call those things for leaks. If not that then the temp switch that turns the compressor on and off might be bad. That is about all I know about a/c systems, except I have recharged them myself.

Dave

Unfortunately it works fine for the first 10-20 minutes, but they don't listen and keep signing off on it when it's cold when it first starts up. I don't think it's a leak because the first time it was not unusual and now it was perfect on the last service, so it's not that. I keep thinking the temp switch or the hi/lo pressure valves I've been hearing about. It's getting aggravating though, especially since it's not under warranty, so that creates new disputes.
 

Dave

Administrator
KJ Supporting Member
KK Supporting Member
Joined
Feb 22, 2006
Messages
15,567
Reaction score
15
Location
on here
Unfortunately it works fine for the first 10-20 minutes, but they don't listen and keep signing off on it when it's cold when it first starts up. I don't think it's a leak because the first time it was not unusual and now it was perfect on the last service, so it's not that. I keep thinking the temp switch or the hi/lo pressure valves I've been hearing about. It's getting aggravating though, especially since it's not under warranty, so that creates new disputes.

From your description then, it seems like they have to let it run for 20 minutes or you have to hyjack the tech and take him for a ride.

Dave
 

trail rated

Full Access Member
Joined
Jan 7, 2009
Messages
138
Reaction score
1
Location
Plant City, FL
An A/C system that blows cold air for awhile then warm air is probably freezing up. This can be caused by air and moisture in the system that allows ice to form and block the orifice tube.

Evacuating the system with a vacuum pump will purge it of unwanted air and moisture. Evacuation should be done with a vacuum pump that is capable of achieving and holding a high vacuum (29 inches) for at least 30 to 45 minutes.

For best performance, an A/C system should contain less than 2% air by weight. For every 1% increase in the amount of air that displaces refrigerant in the system, there will be a corresponding drop of about one degree in cooling performance. More than 6% air can cause a very noticeable drop in cooling performance, and possibly cause evaporator freeze-up.

Air can get inside a system through leaks, by not evacuating the system prior to recharging it, and/or by recharging the system with refrigerant that is contaminated with air. Recovery equipment can suck air into the recycling tank if an A/C system contains air or if the system has a leak. For this reason, the refrigerant recovery tank on recycling equipment must be checked and purged daily. On some equipment, this is done automatically. But on equipment that lacks an automatic purge cycle, tank pressure and temperature has to be measured and compared to a static pressure reference chart.

Some refrigerant identifier equipment can detect air in the system as well as other contaminants. An identifier should be used to check the refrigerant before the system is serviced to prevent cross-contamination of recovery and recycling equipment.

Possible causes of intermittent cooling in a manual A/C system that might be caused by an electrical problem include:

Faulty low pressure cutout switch. This switch prevents the compressor from running if the refrigerant level is low. If the cutout switch is not reading correctly, it can prevent the compressor from coming on.

Faulty compressor clutch. The magnetic clutch on the compressor requires full battery voltage to engage. If the voltage to the clutch is low, or the clutch coils have too much resistance, or the air gap in the clutch is too great, the clutch may not engage to drive the compressor.

Faulty compressor clutch relay. Check to see if the relay is receiving voltage when the A/C is turned on. Also check the relay wiring and ground connections. If bypassing the relay with a jumper wire or routing battery voltage directly to the compressor clutch makes the A/C work, the relay is probably bad.

Faulty A/C control switch. The switch may be worn and not making good contact when it is turned on.

http://www.aa1car.com/library/ac98.htm
 

CMCLEAN

New Member
Joined
Mar 23, 2009
Messages
9
Reaction score
0
Location
Haiti
Also, make sure that your electric radiator fan runs continuiously. I had a bad connection on the fan relay and that caused the A/C to loose it's cooling effect and overheat the engine in slow traffic.
 

desertkj

Full Access Member
Joined
Jan 30, 2006
Messages
3,735
Reaction score
6
Location
Arizona
trail rated, great article. That was the kind of things I've been looking for. I would not rule out moisture in the lines, but more than likely, I am thinking it is one of the electric issues listed at the end. The fan clutch was replaced, so evidently that was contributing to the problem, but not the entire issue.

CMCLEAN, I appreciate the response, but unfortunately, the fan relay was replaced fairly recently on another service, as was the radiator. The Jeep is also not running any hotter in traffic, so the problem seems to be isolated to the air conditioning system. I'm really curious to see what the problem is, as it does not appear to have happened before on the forum and, to the best of my knowledge, I have one of the older KJ's on the board (Built in 01).
 

desertkj

Full Access Member
Joined
Jan 30, 2006
Messages
3,735
Reaction score
6
Location
Arizona
Of course, yesterday for its appointment it was 65 degrees and we could not replicate the problem. Today, about 80, and it seems to only do it when the system is on recirc. I'm starting to not like this thing. :mad:
 

Latest posts

Members online

Top