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A/C Info and Advice

J

JonnyCat63

NAXJA Forum User
NAXJA Member
Location
San Diego
I have a few questions about A/C systems in XJ's, and wondering if I could do some of the work myself. I'm not well versed in auto A/C systems, but I do have a clue.

Here's the deal. My son has a bone stock 99 XJ and the A/C wasn't working. He was going on a road trip, and I didn't have time to mess with it, so we took it to a local shop. They repaired it fine, and did a nice job. They changed the compressor, condenser, accumulator, etc. A/C works great, but it was a little pricey.

So on my 99, I'm having the same problem, no A/C. I tested the compressor with 12v, doesn't come on. I'm thinking I'm in the same boat and need to replace some parts.

This is what I would like to do. I could by an A/C kit from RockAuto (or somewhere else) and change the compressor, condenser, accumulator, etc, myself. After that, I would just take it to a shop to have them put in the Freon and dial it all in.

Here's my questions.
1. Is that a doable plan?

2. What do I do with the Freon that is in the system already? I'm sure it's pressurized. Do I just purge it from one of the ports? How is this done?

3. What parts are specifically needed? I want to change the compressor, condenser, accumulator. The shop changed the expansion valve on my son's XJ, too, but I don't know where that is. There are some other parts listed on the receipt, but I don't know what or where those are.

Has anyone done something similar? Or should I just bring it to the shop and bite the bullet?

Any help or advice would be greatly appreciated.
 
The clutch and the compressor are two different parts. There is a single wire going to the clutch, this wire has been known to break and can sometimes be repaired. There is a coil inside the clutch, nothing more than a large electromagnet. I'd ohm test this coil. The clutch/coil can be replaced with the compressor mounted and may save a costly repair or a whole lot of unnecessary work.
The power for the clutch usually goes through a fuse, a relay, and one or two switches (depending on model) a high-pressure switch, and/or a low-pressure switch.
I'd also test the clutch ground to the case, the mount, and the battery negative just as a ground health check.
 
First, what 8Mud said!!

Next, I think the '99s have 2 wire connectors. When you tested the compressor (clutch) did you apply 12v directly to the coil and ensure the other side had a good ground?

How do you know it still has refrigerant (R-134a not Freon)? If it does, the proper way is to take it to a shop and have them reclaim any remaining refrigerant. You might get a discount on recharging later.

Other than hand tools, you need ac line disconnect tools. Those are the plastic collars that allow you to take apart the quick disconnects.

Use your "SearchFu" and search for compressor clutch air gap. If you energize the clutch directly with 12v+ and it doesn't engage, you can push on the plate and see if it engages (of course, engine off!!!)

Technically, there's no expansion valve. The 99's use a fixed orifice located in the liquid line (Condenser to Evaporator). The orifice itself is not removeable so the line would need replacing.

So it's completely doable. I've done my '88s entire system minus the evap. I do have the gauges and vacuum pump so I charged my own system.

When you go back for charging, they will first pull a vacuum to remove and air, moisture, and check for any leaks. Then charged the system.

If you like, post a picture of your receipt (cover any private info), or just list the part names and numbers.

You can also use the list to buy the parts you need.

Good online sources of parts are:

https://jeepair.com/

https://www.ackits.com/
 
JonnyCat63 said:
I have a few questions about A/C systems in XJ's, and wondering if I could do some of the work myself. I'm not well versed in auto A/C systems, but I do have a clue.

Here's the deal. My son has a bone stock 99 XJ and the A/C wasn't working. He was going on a road trip, and I didn't have time to mess with it, so we took it to a local shop. They repaired it fine, and did a nice job. They changed the compressor, condenser, accumulator, etc. A/C works great, but it was a little pricey.

So on my 99, I'm having the same problem, no A/C. I tested the compressor with 12v, doesn't come on. I'm thinking I'm in the same boat and need to replace some parts.

This is what I would like to do. I could by an A/C kit from RockAuto (or somewhere else) and change the compressor, condenser, accumulator, etc, myself. After that, I would just take it to a shop to have them put in the Freon and dial it all in.

Here's my questions.
1. Is that a doable plan?

2. What do I do with the Freon that is in the system already? I'm sure it's pressurized. Do I just purge it from one of the ports? How is this done?

3. What parts are specifically needed? I want to change the compressor, condenser, accumulator. The shop changed the expansion valve on my son's XJ, too, but I don't know where that is. There are some other parts listed on the receipt, but I don't know what or where those are.

Has anyone done something similar? Or should I just bring it to the shop and bite the bullet?

Any help or advice would be greatly appreciated.
Click to expand...

If you are absolutely sure it is the compressor, I would go ahead and replace everything except for the evaporator core. The parts are super cheap on Rock Auto. When compressors go bad they can contaminate the rest of the system with metal shavings that are hard to flush out.
As mentioned, you will need the tools to disconnect the A/C, A/C flush to flush out your evap core, gauge set and vacuum pump, 2 cans R-134 and the appropriate amount of PAG oil. If need be, I can look that up when I get home.

BTW, connect your drier last so that it is not open to the air for an extended period. Also, read compressor pre-install instructions carefully to see recommendations on PAG oil procedures.
 
Saudade said:
First, what 8Mud said!!

Next, I think the '99s have 2 wire connectors. When you tested the compressor (clutch) did you apply 12v directly to the coil and ensure the other side had a good ground?

How do you know it still has refrigerant (R-134a not Freon)? If it does, the proper way is to take it to a shop and have them reclaim any remaining refrigerant. You might get a discount on recharging later.

Other than hand tools, you need ac line disconnect tools. Those are the plastic collars that allow you to take apart the quick disconnects.

Use your "SearchFu" and search for compressor clutch air gap. If you energize the clutch directly with 12v+ and it doesn't engage, you can push on the plate and see if it engages (of course, engine off!!!)

Technically, there's no expansion valve. The 99's use a fixed orifice located in the liquid line (Condenser to Evaporator). The orifice itself is not removeable so the line would need replacing.

So it's completely doable. I've done my '88s entire system minus the evap. I do have the gauges and vacuum pump so I charged my own system.

When you go back for charging, they will first pull a vacuum to remove and air, moisture, and check for any leaks. Then charged the system.

If you like, post a picture of your receipt (cover any private info), or just list the part names and numbers.

You can also use the list to buy the parts you need.

Good online sources of parts are:

https://jeepair.com/

https://www.ackits.com/
Click to expand...

My 99 has a one wire connector. I checked it with 12v and it does click. So I'm not sure the compressor is bad. The e-fan does not come on when the A/C is turned on inside the jeep. I'm going to jump the low and high pressure switches and see if it's that.

I don't know if it has refrigerant in it or not. I may invest in set of gauges to check that.

I have the A/C line disconnects, I just need to make sure there is no refrigerant in it first.

I'll check the pressure switches today and report back. Thanks for your help!
 
Replacing my entire A/C system for $300.

Search Amazon: "UAC KT 4366A A/C Compressor and Component Kit"
Do a quick compatibility check. (fits my 1996)
 
boncrshr said:
If you are absolutely sure it is the compressor, I would go ahead and replace everything except for the evaporator core. The parts are super cheap on Rock Auto. When compressors go bad they can contaminate the rest of the system with metal shavings that are hard to flush out.
As mentioned, you will need the tools to disconnect the A/C, A/C flush to flush out your evap core, gauge set and vacuum pump, 2 cans R-134 and the appropriate amount of PAG oil. If need be, I can look that up when I get home.

BTW, connect your drier last so that it is not open to the air for an extended period. Also, read compressor pre-install instructions carefully to see recommendations on PAG oil procedures.
Click to expand...

I've read up and watched a few videos on how to do this, so I might go this route you suggested. I would just need to by the gauges and vacuum pump. Everything else I have, plus enough knowledge to be dangerous! LOL!

I'm not opposed to buying more tools and my 95 XJ may need some A/C help, too. So at least it wouldn't be a one off tool buy.

I think the XJ is 8.1 ounces of PAG oil? If you could check, that would be great. Thank you for your help.

I would just need to take it to a shop and have them purge the refrigerant out if it is still in there. Not that I would ever do this, but say hypothetically if someone would need to purge a minor amount of refrigerant, how did they safely do that back in the day? I would never do that as it is dangerous, illegal, and bad for the environment, I'm just curious how it was done prior to recovery systems. I'm in the construction industry, and I know years ago, it was routine for the A/C guys to purge systems on top of the roof into the air. Just curious how it was done.
 
clean96XJ said:
Replacing my entire A/C system for $300.

Search Amazon: "UAC KT 4366A A/C Compressor and Component Kit"
Do a quick compatibility check. (fits my 1996)
Click to expand...

Thanks for the link. I've been looking at the UAC kits on RockAuto. I'm going to do some more tests on the system and see what I find. I'll definitely report back. If the system does need to be changed, I'm pretty sure I'll tackle it myself.
 
I just jumped the low pressure switch and the compressor and e-fan came on. I think maybe its low or out of refrigerant, or it could be a bad switch. I'll check the continuity of the switch first. At this point, I think I need a set of gauges to check. I have a bottle of A/C Pro from Oreilly's. May throw that on there to see if it does anything.
 
I just finished using Arctic Freeze® Ultra Synthetic Refrigerant with dye (Advance Auto). Gauge was in the white area initially so little to no 134 present. With AC running the compressor would not engage at all until I had added some refrigerant, then would cycle on and off every few seconds with minimal 134 until I got sufficient quantity in it to keep it running continuously. Got it to 61* so pleased with that.

Rookie Tip: be absolutely certain the fitting on the hose is properly seated on the low pressure port BEFORE you squeeze the trigger or it will spray dye everywhere, which will destroy any ability to see where it's leaking until it's cleaned off. Hopefully a pressure washer will remove that pretty green stuff. Other than the oops factor it was a simple operation. I picked up a variety of AC o-rings in case I find a leak that simple.
 
So here is an update. I changed the low pressure switch with no change. So I decided to dump some Arctic-Freeze that I had. System started cycling on and off, but briefly. I put more in and it started cycling for longer periods. I just kept putting more in until the gauge on the can was in the green range. A/C blows cold now. Looks like it was just low on refrigerant. In hindsight, I should have just bought the gauges, but now I know. The switch wasn't much, so no harm there. That and the can of Arctic-Freeze was less than a set of gauges. Even still, it's been worth it to learn more about A/C systems.

I realize this could be a temporary fix, as it could have a leak or other problems. I'm going to run it like this for a while and see what happens.

If I do need to change out the system at a later date, I will invest in some gauges and a vacuum pump, and try it myself.

Thanks to all of you for the advice, I learned a lot. I wasn't well versed in A/C systems, but now thanks to you guys, I have a lot more education and understanding, and will have no problem fixing future problems myself.

Good stuff and good people here on NAXJA!!!!
 
You can check for leaks with a UV light if the Arctic had dye in it (light included). Parts stores have specific o-rings or a kit of varying sizes for an easy fix if it's that simple. That's what I'm hoping for.
 
JonnyCat63 said:
So here is an update. I changed the low pressure switch with no change. So I decided to dump some Arctic-Freeze that I had. System started cycling on and off, but briefly. I put more in and it started cycling for longer periods. I just kept putting more in until the gauge on the can was in the green range. A/C blows cold now. Looks like it was just low on refrigerant. In hindsight, I should have just bought the gauges, but now I know. The switch wasn't much, so no harm there. That and the can of Arctic-Freeze was less than a set of gauges. Even still, it's been worth it to learn more about A/C systems.

I realize this could be a temporary fix, as it could have a leak or other problems. I'm going to run it like this for a while and see what happens.

If I do need to change out the system at a later date, I will invest in some gauges and a vacuum pump, and try it myself.

Thanks to all of you for the advice, I learned a lot. I wasn't well versed in A/C systems, but now thanks to you guys, I have a lot more education and understanding, and will have no problem fixing future problems myself.

Good stuff and good people here on NAXJA!!!!
Click to expand...

Good news! I just bought a new to me XJ in November 2020. It was low on freon so I added a can, and knock on wood it is still blowing cold. But yeah, if it leaks out just figure out where it is leaking from and report back.
 
I thought I would piggyback on this thread. I'm fairly new to XJs - has one for a bit then let it go and back in the game with a 1998 with 175K on it. I bought it sight unseen from a local based on videos and generally it's in decent shape. It's running a a little rich - throwing the P0172 code, but working on chasing that down.

Biggest drawback - no A/C - and by no A/C I mean the ENTIRE system has been removed. No compressor, condenser, lines...so I guess my question is - in your wisdom where do I start if I want to install a new system? Where do I start trouble shooting and making sure I have what I need electrically, and outside of the components to support a new system. I can get to installing the new system later, but I don't want to just start buying parts willy-nilly to find out it's unworkable due to something the last guy did inside somewhere else....hope this makes sense and willing to offline about it if there are any AC wizards out there!
 
Fortunately, there aren't too many hard parts and also, they aren't terribly expensive. I think where I might start if I was you is to inspect the wiring harness and if the A/C related bits were left intact. If not, start combing salvage yards and try to find the relevant intact harnesses.

Is the heater core/evap core still in place? I'm no A/C wizard but I have replaced every component at one time or another. The XJ's are pretty simple to be honest.
 
BTW, just trying to remember off the top of my head the connections inside the engine compartment and I think there are only 3. One plug to the compressor, one to the pressure switch on the hard line on top of the compressor and one on the receiver/dryer.
 
Thanks boncrshr --- well - I feel kinda stupid now, but need to ask. Was there an option in 1998 for no A/C? Just curious - because it just seems weird. There is a dummy pully where the compressor should be. No lines going through the firewall. I mean - someone must have REALLY hated air conditioning to remove all this. Any thoughts? And if so, I guess I could retro-fit with A/C based on what seems to be a fairly simple system. I'm going to check the heater core once I get it back from the shop for other issues...
 
I think XJs for the Forestry Service and other GSA/fleet procured vehicles may have been AC-less. Many Postal Service XJs are even RHD.
 
I had the base model 98 xj it had air conditioning power mirrors am FM CD player idiot lights for gauges.
 
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