A/C not working on 1999, need assistance.

[Mudderoy]

I jumper-ed the "thing" that tells the clutch to engage on the a/c compressor. The electric fan comes on but the clutch never engages.

:check: Checked 20 amp fuse that is marked on the fuse box for the clutch
:check: Swapped clutch relay from my 1998
:check: Checked connection running to front of compressor and into clutch
:check: Put clutch relay from 99 in the 98, clutch engaged.

What else?

[4.3LXJ]

So compressor runs and it is blowing warm air?

[oderdene]

pressure switch ?

http://www.askamechanic.info/askamech2/images/stories/Cherokee%20AC%20Stops/Pressure%20switch%20schematic.JPG

[bigjim350]

Can you turn the clutch in the center of the comp by hand while the motor is off? If not, its time to replace comp.

[Mudderoy]

Can you turn the clutch in the center of the comp by hand while the motor is off? If not, its time to replace comp.

Yep it turns pretty easy.

[Mudderoy]

I took a BFG to it and hit on the top of the clutch while it was jumpered, a/c on and engine running. Finally the clutch engaged.

I put in oil, sealant, and several cans of r134, temp got down to about 70. I think it was leaking out almost as fast I was putting it in, or the clutch wasn't engaging fully.

If I turn off the A/C and turn back on the efan turns off and back on but the clutch won't start turning on it's own.

The guy at the used car lot had a snap on sniffer and he was picking up r134 at the firewall where the lines run in.

[BigJeepBigJeep]

The o rings in the ac block are probably worn and leaking.

Sent from my SGH-T839 using Tapatalk

[Mudderoy]

The o rings in the ac block are probably worn and leaking.

Sent from my SGH-T839 using Tapatalk

What is an a/c block?

[jccatt]

When you fix you 99 a/c can you fix mine muddy :-)

[BigJeepBigJeep]

When the line leaves the A/C drier, it runs to the firewall where it meets the condensor which is under the dash. There should be a junction there with O Rings for the two lines to go to/from the condensor.

Now mind you I restore(d) classic nissans for a living so I'm just going by that, I haven't fiddled with a Jeep A/C system quite yet. Its all the same idea though, so it should be very similar.

Maybe if I get a day free I could bring my UV detector and find the exact leak.

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[BigJeepBigJeep]

Correction, I meant when the line leaves the drier and goes to the evaporator under the dash. The condensor is in front of the radiator.

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[4.3LXJ]

The R12 systems have a block called a TXV (thermal expansion valve) The R134A systems have a fixed orifice instead which looks like a fat part of the line before going into the evap coil.

[Mudderoy]

When you fix you 99 a/c can you fix mine muddy :-)

It looks like mine is going to require another compressor because the clutch will not stay engaged. Also after getting the temp down to around 70 degrees it all leaked out almost as fast as I put it in.

I'll get it working but it's going to require a little more effort.

[XJ4IV]

Im not sure about all this high tec stuff... but my cherokee A/C system is very simple and is as follows...
in this pic you will note there is a diagram of what looks like a window related to the two lowest switches
http://static.howstuffworks.com/gif/vehicle-pictures/2001/jeep/cherokee/0659-040-driver-side-window-control-480.jpg
while driving at speeds between 45 and 70 if you engage these two buttons simultaneously you will get a rush of cooler air however the down fall to this is you must keep your driving speeds upwards of 50mph+.
Other options I have seen is this
http://i85.photobucket.com/albums/k49/bldeagle10/mopar-xj-stroker.jpg
or this option

http://www.jeepz.com/forum/attachments/cherokee-commander-wagoneer-liberty/5354d1276614563-so-i-have-ask-topless-cherokee-2.jpg
Orrrr you can mix and match them
http://i22.tinypic.com/16bfpxd.jpg

[4.3LXJ]

Ah yes, 4 - 80 AC

[Weldmen]

If the preasure is to low in the A/C system the pump clutch will not engage. To find this out you can put a jumper wire in the switch N/O if the pump comes on then thats your problem. To low of preasure in the system.
The plug is on top of the bottle.

http://abuncha.biz/pics/plug.jpg

[Mudderoy]

If the preasure is to low in the A/C system the pump clutch will not engage. To find this out you can put a jumper wire in the switch N/O if the pump comes on then thats your problem. To low of preasure in the system.
The plug is on top of the bottle.

http://abuncha.biz/pics/plug.jpg

If you re-read my original post...


I jumper-ed the "thing" that tells the clutch to engage on the a/c compressor.

[Weldmen]

If you re-read my original post...

Ya ok. Stupid me.

[Mudderoy]

Ya ok. Stupid me.

Hey no offence intended I just wanted you to know I had done that. ;)

[Weldmen]

No offense taken. I must have missed it. NBD
We all have our moments right. Just trying to help out, I don't claim to know everything like some other sites.... :D

[Mudderoy]

No offense taken. I must have missed it. NBD
We all have our moments right. Just trying to help out, I don't claim to know everything like some other sites.... :D

I was talking to msmoorenburg Saturday afternoon. He says it's probably just "O" rings, and since the clutch isn't working 100% I should replace the compressor.

I need to get a set of gauges and a vacuum pump.

[Weldmen]

I was talking to msmoorenburg Saturday afternoon. He says it's probably just "O" rings, and since the clutch isn't working 100% I should replace the compressor.

I need to get a set of gauges and a vacuum pump.

If I am not mistaken I believe you can just replace the clutch portion of the unit. That would save you a ton of cash.
Also I have have a pump from a 1979 Mustang 5.0 with the clutch. Dont know if it will work but you could just have it. Shipping of course...:eek:

[4.3LXJ]

X2 :thumbsup

[jccatt]

Sounds like my A/C problem is similar to yours Tony. Turn on and it engages for a sec and goes off. Do you have heat?

[Mudderoy]

Well only the wicked are lucky it seems.

The compressor clutch was an issue, so we put a compressor on from a wrecked 2001.

Replaced the "O" rings on everything, still wouldn't hold a vacuum.

Matt took the dash out of the 2001 and retrieved the evaporator.

Then he took the dash out of the 1999 and install the evaporator from the 2001.

Hooked the A/C stuff back up and it held a vacuum. For the next 1.5 hours Matt worked on re-installing the dash on the 1999.

The temp, according to the temp probe stuck in the middle vents, read 42 on 1+ hour drive home.

My wife was waiting to be picked up by her parents to attend a wedding. I made it home in time for her to take the 99 Jeep and ride in comfort!

[4.3LXJ]

Good deal. Glad you got it running right.

[Mudderoy]

https://lh6.googleusercontent.com/-kYV0ZAh9D6g/TfP3gNIm75I/AAAAAAAAA6Q/jDOBBgQi3yw/s640/2011-06-11%25252011.57.46.jpg

https://lh4.googleusercontent.com/-9LfhAZItMNs/TfP30OQ4myI/AAAAAAAAA6U/PMwswEQudNU/s640/2011-06-11%25252012.18.23.jpg

https://lh3.googleusercontent.com/-im-TUGJ93Dg/TfP4hCwH78I/AAAAAAAAA6Y/eVCsQ8XtkhY/s640/2011-06-11%25252012.49.42.jpg

https://lh5.googleusercontent.com/-C_R_zuAoilA/TfP4z5iSCwI/AAAAAAAAA6c/KOY_7m4gGXs/s640/2011-06-11%25252012.49.53.jpg

https://lh3.googleusercontent.com/-JH3AfE2v4Ho/TfP5QBKrPtI/AAAAAAAAA6g/v66fAO2XX7E/s640/2011-06-11%25252013.12.03.jpg

[msmoorenburg]

yup i'm tired now :indifferent0020:

[LizardRunner]

Way to go Matt! at least I know my air problem is just the O rings at the firewall. should be a much easier fix for me.

[Mudderoy]

Way to go Matt! at least I know my air problem is just the O rings at the firewall. should be a much easier fix for me.

Yeah I learned some good stuff. I was reminding my wife that when we have the 95 Ford A/C fixed it was estimated at $1200. If the evaporator turned out to be bad it would be $2400. They said they wouldn't know until they started working on it. Fortunately (if you can call it that) it was only $1200.

For the Jeep anyway, the compressor is $187 to $340. The evaporator was $129 from a local autoparts place. The "O" rings mega pack was $22. The R134a for a case was $87, we used 2 cans ($28 if bought individually).

So $1200?!?!?! Hell yeah I'd do 3 A/C jobs a month and live a great life!

[LizardRunner]

I know what you mean tony. I was telling wolf that I am going to buy a vaccum pump for when I fix my O ring leak. it would cost more to have it done than to buy the pump and do it myself. plus I would then have a vaccum pump for guitar building and other stuff, like if her air con ever goes out in the van. makes perfect sense to me, suprisingly, it did to her too.:D

[Mudderoy]

I know what you mean tony. I was telling wolf that I am going to buy a vaccum pump for when I fix my O ring leak. it would cost more to have it done than to buy the pump and do it myself. plus I would then have a vaccum pump for guitar building and other stuff, like if her air con ever goes out in the van. makes perfect sense to me, suprisingly, it did to her too.:D

Matt can correct me on this, but he was telling me you don't need a vacuum pump. As long as you change the "O" rings and put the system back together quickly you won't have a problem. It's the moisture from the air that gets into the system and causes problem with the compressor. The vacuum pumps lets you check for a leak, verify that the leak has been fixed, and removes all the water from the system.

A buddy of mine told me to check the pawn shops for vacuum pump and a set of gauges. Probably now is a really good time to find both of those.

[LizardRunner]

yep. I live in humidity ville lol I have at least one set of gauges.

[Mudderoy]

Air conditioner compressor started short cycling. I put some stop leak and some R134a in it.

[Mudderoy]

Looks like I'll be installing a new dryer. Temp won't get below 60 degrees. :(

[TeXJ]

Im not sure about all this high tec stuff... but my cherokee A/C system is very simple and is as follows...
in this pic you will note there is a diagram of what looks like a window related to the two lowest switches
http://static.howstuffworks.com/gif/vehicle-pictures/2001/jeep/cherokee/0659-040-driver-side-window-control-480.jpg
while driving at speeds between 45 and 70 if you engage these two buttons simultaneously you will get a rush of cooler air however the down fall to this is you must keep your driving speeds upwards of 50mph+.
Other options I have seen is this
http://i85.photobucket.com/albums/k49/bldeagle10/mopar-xj-stroker.jpg
or this option

http://www.jeepz.com/forum/attachments/cherokee-commander-wagoneer-liberty/5354d1276614563-so-i-have-ask-topless-cherokee-2.jpg
Orrrr you can mix and match them
http://i22.tinypic.com/16bfpxd.jpg

:jumping0041:

[TeXJ]

https://lh3.googleusercontent.com/-JH3AfE2v4Ho/TfP5QBKrPtI/AAAAAAAAA6g/v66fAO2XX7E/s640/2011-06-11%25252013.12.03.jpg

my flapper in that is what is bad, If i turn it to "4" speed i can hear the flapper shut and the air/heat goes in the dash... :(