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skatulaki 06-07-2021 06:13 PM

2002 Grand Cherokee A/C Blues
I have a 2002 Grand Cherokee that I bought back a few years ago, the A/C worked when I first got it, but it never really worked well and eventually quit working. This year I vowed to get it working. I work road construction and being on 300 degree asphalt in 100 degree heat all day, I'd like to drive home with working A/C.

So anyway last time I tried to get it going I had to replace blower and resistor, and got it going the best it ever worked. 2 days later the refrigerant all leaked out. This time I found the main hose had a bunch of pin holes in it, so I got a new one, and charged the system back up, looked up the amount its suppossed to have, 27 ounces, so I put 2 full cans plus a little from a 3rd. It was blowing as cold as it ever did. I thought hey I'm good to go this time. Again worked good for 2 or 3 days, then nothing. Thought it had all leaked out again, it hadn't. Thought maybe I overcharged it, so I vented some like I did last time I overcharged it, thinking it would go back to working again like last time. It didn't. So now I start looking elsewhere. I find A/C clutch fuse blown, robbed one from my Dodge, and it blew instantly. Got out the multimeter, 12 V on one side, no continuity to ground on the other. Hmmmm

Thought about it, and remember I didn't have the A/C switch on when I put the meter on it.

Next steps, put another fuse in it leaving the A/C switch off, see if it blows, if not, then pull it out and check for a short with the A/C switch on.

Any help will be appreciated! Thanks in Advance!

Additional thoughts. Right about the same time that the A/C quit this time, I noticed the display in the radio has also quit working. The radio itself works, just not the display. Also for some time the turn signals have been intermittanly failing, and working. When i crawled under it. I noticed a connector under the A/C compressor that was soaked with what I believe to be radiator fluid, Looks like the radiator hose above it is leaking. ( another job to do ) I don't know if Antifreeze is conductive or not.

jtec 06-07-2021 06:41 PM

lucky for you one of the gang in the WJ forums is an AC technician, many years learning and working AC. Hope he is done fishing and can chime in.

Lets give him some background to work with, is this a manual or ATC hvac control system, you replaced the hose - you did pull a vacuum? What were the low and HIGH pressure readings? Have you checked for codes post all codes?

WJ60 06-07-2021 08:17 PM


Originally Posted by skatulaki (Post 41288169)
When i crawled under it. I noticed a connector under the A/C compressor that was soaked with what I believe to be radiator fluid,

You need to pull the connector and clean both male and female parts with some cleaner. Replace the fuse and see if it runs.
As Jtec said, I hope you ran the system on a vacuum pump for a while. If you didn't then you'll have to remove all Freon and vacuum it.You should pull it down to 29-30 in.hg, (or under 500 microns if you have a micron gauge), and it should hold there for at least 30 minutes. If it does, then you want to make sure that there is no air in the hose your using to charge the system with. You need to charge the system with liquid into the high side first (engine off), and top it off with liquid into the low side once you get it up and running. Keep in mind that hoses hold Freon and you have to account for that when charging 27 ounces into the system.

skatulaki 06-07-2021 08:36 PM

I don't have all of those answers, I did buy a guage kit to check the high and low, but have not actually checked yet. I am determined to learn how to do A/C properly. I'm a DIY , been a repairman all my life, mostly copy machines, but do my own auto work, and grew up on a farm repairing a lot of farm equipment, and currently as a road striper, have to repair company equipment.
That having been said, I don't know much about A/C or Auto Transmissions. I am bent however on learning A/C.

I did NOT pull any vacume when I replaced the hose, that doesn't mean that I didn't accidently pull one doing something else. There was no vacume to pull in replacing the hose. One end connected to the compressor, the other to the firewall.

I do not know the difference between manual or ATC HVAC. I have not checked for codes, but I can do that, never saw anything in the dash to suggest a code was activated. So it didn't occur to me to check.

I will look for unplugged hoses, and get back! Thanks in Advance!

skatulaki 06-07-2021 08:44 PM

Thanks for that info, A little over my knowledge atm, but I am determined to learn, I might need to buy more equipment. I currently have no means to recover the refrigerant, what is your recommendation?

skatulaki 06-07-2021 08:51 PM

Also when vacume was first discussed, I originally was thinking of vacume hoses, but your post suggests otherwise, bear with me please.

WJ60 06-07-2021 08:51 PM

You must use a vacuum pump before charging any refrigerant system. Air and moisture in the system can cause serious issues. Before going any further you should acquire, or rent, one. So far as removing the Freon, that requires a reclaim machine and a reclaim tank. For that you'll probably have to go to a shop.
I highly recommend watching some Youtube videos before proceeding.
Don't hesitate to asks questions. We're here to help.

HarryH3 06-08-2021 07:04 AM

We don't know where you are, but in the US you can 'rent' a vacuum pump from many auto parts stores for free. You basically pay for it when you pick it up, then they will refund the money when you return it. You should watch a few YouTube videos on charging auto a/c systems before you hook up the gauges. They can be dangerous if you open the wrong valve at the wrong time. You'll also need to learn how to purge the air from the hoses before adding refrigerant.

Note that a/c work can be dangerous! A large leak can freeze skin, eyeballs, etc. quicker than you can pull away. I wear a full face shield at all times and welding gloves while I'm purging the gauge hoses. Yeah, it's awkward, but so is frostbite. ;)

Some shops will evacuate the old refrigerant for DIY'ers for a few bucks. Others don't want to be bothered unless they can also empty your wallet fixing the system themselves.

Another though just occurred. Check the valve that attaches to the can on your new gauge set. Is the pin that goes into the can pointed, or flat on the end? The cans have changed recently, to minimize leakage into the atmosphere after a can is opened. With the old cans, the valve just pierced a hole in the top of the can. Great for getting the gas out, not so great for keeping any remaining gas in. :( Partial cans typically would leak out over a day or two, even with the valve closed. All of the cans that I've see recently for sale have the new self-sealing valve on top. I had to purchase a new valve that has the proper pin, so as to not damage the self-sealing valve on the cans. I got this one: That's the style that you need for the self-sealing cans. When you use a partial can, you can now just open the valve all the way, then unscrew the can from your gauge set, and it should seal itself closed.

Spinifex 06-09-2021 01:14 PM

Yeah it would be worth recovering and pulling a vacuum again, depending on where you are the A/C refill bottles are relatively cheap. Recovery is more of the problem/cost.
But as mentioned there are stores that rent the equipment - you can even buy it all at Harbor freight for less than what you'd probably be charged at a shop for 1 refill.

There are some great YouTube how-to's on how to recover vacuum and fill the A/C, it's only 1 additional step to what you've already done so pretty easy and will allow you to do a leakcheck.

Here are a couple of youtube examples : /
One thing to note if you're renting a vacuum pump - make sure it is full of oil before you leave the store. You don't want to be on the hook for burning out the pump. There is a sightglass on them and a level marking. The stores usually carry the oil to refill it.

Back to your problem though - it's possible that the additional air in the system was causing your pressures to spike and inhibit the compressor, but that doesn't match with your issues on the blown fuse. IMO this sounds unrelated to not performing the vacuum evac.

With the switch ON and the fuse removed see if you have continuity to ground. Clean up the terminals and connectors as suggested because fretting and corrosion can cause high resistance in the circuit. Check continuity between the fuse and the connector to the A/C Clutch.
If the circuits are all good then there may be an issue internal to the clutch.

skatulaki 06-09-2021 07:10 PM

I guess my reply didn't post

1. I drove to work and back fuse didn't blow, ( I did not press AC button ) when I got back I pressed the button and it blew.

2. I checked the non power fuse side, with AC switch off, no continuity to ground, with AC button on dead short !

3. For the fun of it. I connected my new gauge kit The reading probably don't mean much since the system wasn't running, but I thought I would do this in case it does.

40 psi low Just short of 50 high

Since the short seems to be between the switch and the compressor, I'll start by unplugging the compressor and work back from there.

Spinifex 06-09-2021 09:58 PM

Yep sounds like you're on the right track. Good luck hunting down the short! Will be curious to see where it ends up being.

skatulaki 06-11-2021 07:45 PM

I believe I found my problem ! Yay

I picked up where I left off, only first I checked the clutch relay, and wires there, just because they were easily accessible, the only difference made was that the short was then detectable at a relay wire instead of fuse wire, but it at least ruled that out.

In the meantime I learned that I not only had to have the AC switch on but the Jeep running as well.

Next, despite a hot engine I was able to remove the air cleaner and disconnect the connector I believed to be going to the compressor. It was getting dark so I got a trouble light out, and when I started to inspect the harness going to the compressor something immediatly caught my eye, the two wires had some how became pulled down a couple inches of slot in the plastic protective tubing that surrounds the harness. The wire insulation didn't look right, so I peel off 5 or so inches and ran my fingers over the wires and about 2 inches of insulation just flaked off. I separated the wires and viola, no more short !

NOW TO FIX IT ! I stopped there for the evening to contemplate my repair. There is not a lot of wire there to just go and cut and splice, solder, and cover with shrink tube. The bare wires seem to be ok, so I'm not inclined to cut them, but I'm also not inclined to just wrap in electrical tape either, electrical tape probably wouldn't handle the engine heat there . I have some Flex Glue rubberized adhesive, but that takes 24 hours to cure, and I don't know how well it takes the heat. OR I may just go buy another tube of Plumbers Putty ( I swear by this stuff ) its a 2 stage epoxy just cut a chunk off keep squeezing and kneading it between your fingers, and when it starts getting warm I could squeeze it around those wires and make a coating. I know it will handle the heat because I patched a hole in the plastic part of a radiator a little bit bigger than a pencil, and it held for more than a year and still holds, I bought a new radiator but keep the patched one for a spare. I also patched a Brake Fluid resivore too, and it still holds a year later, going to replace that too.

Maybe you guys know something better! Thanks in advance!

skatulaki 06-12-2021 11:30 AM

Well I patched the wires and everything worked, got my gauges out, and charged it up to 45 low a little over 200 on the high. I left it there as refrigerant started dripping out of the high side knob on my gauges, not sure why this happenned unless the gauges are defective in which case I can return them.

The only problem I have now is no air coming from the passenger vents, Just the middle and driver side. It doesn't freeze me out of it , might if the blower blew more air. I don't know if there is a better blower. But its as cold as I have ever had it work.

WJ60 06-12-2021 11:51 AM

If your gauge is leaking freon, then when you pulled a vacuum, you have most likely pulled air and moisture into the system.

HarryH3 06-12-2021 01:03 PM


Originally Posted by skatulaki (Post 41291625)
The only problem I have now is no air coming from the passenger vents, Just the middle and driver side. It doesn't freeze me out of it , might if the blower blew more air. I don't know if there is a better blower. But its as cold as I have ever had it work.

If you have the dual-zone climate control, then perhaps a motor that controls airflow is broken.

If you have the single control climate control, then there's a 99.9% chance that the foam seals in the a/c ducts have crumbled to dust so that now much of the air is leaking out under the dash. Fixing that is quite an undertaking. :( See for the gory details. It's quite an undertaking, but the difference in airflow afterwards is amazing.

(This may also be a problem for the dual-zone systems, but I'm not certain).

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