Cold Air From A/C Stops After 10 Min. - Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ Tech Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 07-29-2009, 12:37 PM   #1
Jeeper
 
fishinVA's Avatar
 
Join Date: Jul 2009
Location: Richmond, VA
Posts: 18
Cold Air From A/C Stops After 10 Min.

Hey, everyone. I've had my four banger TJ for about 13 years, but just now stumbled upon this site. I'm glad to have found it, and have enjoyed a lot of the posts I've read so far.

I've now got a question about my A/C. I had a leak in my A/C last year and had it repaired. The A/C ran great for about a year, but it's now starting to give me fits. When I start the engine, the A/C will blow cold and act normally (air blows out the right vents and I can properly vary air strength). However, after about 7-10 minutes, the air starts to warm up and will eventually blow hot. It's like clockwork each time I run the A/C. I first thought that my coolant was low, but this has been going on for months, and I would think that by now it wouldn't blow cold at all if my coolant was low.

Someone suggested that there might be a problem with the ventilation to the compressor and that once pressure builds up inside, the compressor stopps blowing cold air.

Does anybody have any suggestions or experience with this sort of problem?

fishinVA is offline   Quote
Old 07-29-2009, 12:48 PM   #2
Jeeper
 
Join Date: Jul 2009
Location: Detroit, Mi
Posts: 26
I just posted this for someone else too. Could be this.

Check the High and Low pressure switches. I had the same problem on my Mustang. I was able to apply pressure on the electrical switch that plugs into the system. When playing around with it i could get the compressor clutch to kick on and off. This might be happening for you too.

Jeepster0619 is offline   Quote
Old 07-29-2009, 03:22 PM   #3
Jeeper
 
fishinVA's Avatar
 
Join Date: Jul 2009
Location: Richmond, VA
Posts: 18
Thanks for the tip. Sorry, I didn't see that thread earlier. I'll try that and see if it works.
fishinVA is offline   Quote
Old 07-29-2009, 05:12 PM   #4
Jeeper
 
Join Date: Aug 2008
Posts: 2,473
When the freon gets low - 'cause of a small leak somewhere, it can do that.

What happens if it's got a low charge of freon there is enough liquid freon to compress and circulate - get cold, but as it circulates it's spread throughout the entire system, condenser, evaporator and everything else. The compressor starts running out of liquid freon to pump. Pressure drops, then the low pressure switch senses it's low on liquid, and cuts off the clutch.

Once it's shuts off, the freon liquefies again, pressure rises enough to satisfy the switch, compressor restarts - to do it all over again. It cycles like that.

So the effect is it's cool for a few moments, then stops working.

Icing can be another cause, but unless someone's had the system open it's not likely that.

Try adding 1 can - no more. Put a thermometer in a vent and watch the temp. Doors and windows closed. You won't be able to get enough in unless you have the engine running. Run at idle, with the freon can right side up - valve at the top - shake it every minute or so. The can will feel cold if it's feeding.

Take your time - the aftermarket do-it-yourself kits have a very small orifice - for your protection. With a larger orifice turning the can upside down could hydraulic the compressor, ruining it.

Always add it to the suction side - never the high side. If you are using one of those "do it yourself" kits it will only attach to the low side anyway.

You should see the temp drop down. Watch carefully - the temp will drop as you add - but when it stops going down and starts back up STOP ADDING.
It's full.

It may take a second can to hit that lowest spot.

You may have a small leak and have to add a little every so often.

Harbor Freight - and Ebay, has nice little electronic detectors for finding freon leaks - about $30.

Using a pressure gauge with the engine off tells very little, -- it just says there is something in it - enough? Who knows.
The engine must be running and the compressor clutch engaged to mean much.
__________________
It's no wonder the country is falling apart - stupidity abounds!
rrich is offline   Quote
Old 07-29-2009, 10:57 PM   #5
Jeeper
 
fishinVA's Avatar
 
Join Date: Jul 2009
Location: Richmond, VA
Posts: 18
Thanks for the help. If checking the pressure switches doesn't work, I'll have to dig deeper with what you've told me and see if that will work.
fishinVA is offline   Quote
Old 07-29-2009, 11:39 PM   #6
Jeeper
 
Join Date: Aug 2008
Posts: 2,473
I believe you have only ONE switch - it is a combination Lo & Hi switch.

The only thing you can check is the connections to it.
You'd have to apply various pressures to see when it switches. You'd need a special test set-up to do that.

They rarely go bad anyway.

You can jumper across the 2 wires to activate the clutch - it will stay on constant. But that won't tell you anything other than the clutch works. If it was totally empty doing that helps you fill it by having the compressor sucking.

Add one can and see if it starts blowing cool and stops the cycling - or most of it.
__________________
It's no wonder the country is falling apart - stupidity abounds!
rrich is offline   Quote
Old 08-22-2015, 08:34 AM   #7
Newb
 
Join Date: Apr 2015
Posts: 1
Hi averyone. I am kind new here. I have a AC problem with my jeep TJ. Here is what is does. I turn on the AC and is come out cold for few mins then the clucth of the compressor stop then on again and stop and on is keep doing that all the time. And i get a warm air coming out. Anybody know the problem? Please help me. Thank you very much in advance
99_KuBi_TJ is offline   Quote
Old 08-22-2015, 08:43 AM   #8
Supporting Member

WF Supporting Member
 
JimsJeep's Avatar
 
Join Date: Feb 2012
Location: Long Branch NJ
Posts: 2,022
Quote:
Originally Posted by 99_KuBi_TJ View Post
Hi averyone. I am kind new here. I have a AC problem with my jeep TJ. Here is what is does. I turn on the AC and is come out cold for few mins then the clucth of the compressor stop then on again and stop and on is keep doing that all the time. And i get a warm air coming out. Anybody know the problem? Please help me. Thank you very much in advance
Most likely your system is low on charge. Compressor engages and the suction draws the pressure down on the low side until the low pressure switch shuts it off, then pressure equalizes and the cycle starts over.
__________________
1999 Wrangler Chili Pepper Red

Google is your friend.
JimsJeep is online now   Quote
Old 08-22-2015, 09:30 AM   #9
Jeeper
 
GlennB's Avatar
 
Join Date: May 2015
Location: Huffman, Tx (outside of Houston)
Posts: 302
All of the above are good tips. Check you fan as well. If you don't have enough air going through your condenser (in front of radiator) the switch will shut down your AC.
The AC high pressure line from the condenser to the orifice tube will get very hot!
Good luck!!
GlennB is offline   Quote
Old 08-22-2015, 12:02 PM   #10
Jeeper
 
Join Date: Oct 2014
Posts: 17
when i installed my ac kit into my tj, i went to auto zone and rented an a/c manifold gauge. you can then monitor the high and low pressure lines and make sure you add the correct amount of refrigerant. this will also tell you if youre low or too full on refrigerant. i used this chart as a guide when i charged my system.

97_4.Oh is online now   Quote
Old 08-22-2015, 01:31 PM   #11
Jeeper
 
GlennB's Avatar
 
Join Date: May 2015
Location: Huffman, Tx (outside of Houston)
Posts: 302
Great chart 97_4.0h
Also gauges are available at Hazard Fraught tools for not a lot of money. If you know how to read them they are well worth it and it'll save money in the long run.
Keep in mind that blower speed will raise temps and pressures. Pressures will be lower at lower blower speeds.
GlennB is offline   Quote
Old 08-22-2015, 01:46 PM   #12
Jeeper
 
Wattapunk's Avatar
 
Join Date: Mar 2012
Location: North TX
Posts: 2,351
After you rule out a compressor issue, I would next suggest checking the blend door that controls air temp. Follow the temp slider cable to its endpoint. When it blows hot, try manually turning the blend door to see if the temp changes.

Wattapunk is offline   Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
any ideas? cold start problems calimbrium General Jeep Discussion 3 07-28-2009 12:02 AM
Bump stops bottoming out cnolan76 TJ Tech Forum 18 04-06-2009 09:14 PM
Severe cold weather driving scotiez General Jeep Discussion 4 02-03-2008 06:36 AM
Bump stops question Jma20a TJ General Discussion Forum 7 06-28-2007 04:43 PM
Cold Start Noise dcrolin TJ Tech Forum 2 01-25-2007 06:15 PM



Download our Mobile App

» Featured Product

All times are GMT -5. The time now is 07:09 AM.


User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC