A/C will only blow through defrost vents - Page 2 - JeepForum.com
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post #16 of 49 Old 06-26-2013, 11:25 AM
Uniblurb
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Quote:
Originally Posted by TontoKowalski View Post
You guys were right, it was in a vacuum line...

I got home last night and decided to try and fine this line that goes up under my batter, who designed that btw?

I found it, took the battery and tray out inspected the line and the box that it goes into, didn't see any abnormal wear and tear. I did happen to have extra hose laying around so I just replaced that section...what is that box btw?

So then I followed it back to the firewall. Where the hose T's off, there is a thin hose that shoots up into the firewall. Somehow, somewhere that tiny hose snapped.

Now, from the T, the tiny hose fit into a thicker outer hose. So I removed that hose and noticed that the firewall part of the hose broke off inside of the larger housing hose. I tweezed that piece out...struggled to get my fat hands back there against the burning engine block, etc...and inserted the tiny tube into the larger tube.

I was 100% skeptical that it would work. I put the key in, turned it on and in about 5 or 10 seconds the thing started pumping out of the dash vents.

Eureka! Now...anybody got any tips on re-juicing my AC system so it's like a meat locker when I drive?

Thanks for the advice fellas, worked out fine...
Glad you got it fixed! The bottom of the battery tray is the vacuum reservoir and the tube/fitting you attached the rubber hose to is a one-way check valve. The reservoir stores vacuum until it's needed like when climbing a hill or under hard acceleration. The main purpose of the reservoir is too supply vacuum to the speed control servo (cruise control) so it continues to function properly. But if there's a leak in the hose, or the reservoir is cracked, their isn't enough vacuum to work the HVAC control switch.

The little black vacuum line which goes through the firewall is notorious for breaking after becoming brittle. You're lucky it broke at the T and were able to fix it. Mine broke once at the hole next to the evaporator tube and I was darn lucky to be able to fish the tube back up through the foam insulation in the hole w/a small pair of needle-nose to repair it. Not much slack at all in this tube either.

The correct method for recharging your AC system is to go get a set of loaner manifold gauges from Autozone and/or Advance. You have to pay full price ($100-$150), can keep for 90 days, and return for a full refund. The ones I borrowed from Autozone didn't have instructions so I just looked up the brand/model and downloaded them. Then you just connect the two outside gauge lines to the low pressure port usually in the liquid/orifice tube and high side at the compressor discharge fitting. You can't reverse them since they're different size fittings. You'll also need to buy a valve (about $12) for attaching a can of 134a to the yellow middle suction hose of the manifold gauges. Then you open only the low side of the gauge set for recharging. Plenty of good video on the internet on how to do this.

Some will just but a can of 134a with a gauge/hose on it but these gauges can be highly inaccurate and you don't want to overcharge the system. Since the AC system is a closed system if you're low on 134a you have a leak somewhere. So best to buy a can or 2 of 134a with UV dye in it for checking for leaks. I also bought a pair of yellow glasses and UV pen light from Autozone for $12 so I could see the dye easily.

Unfortunately on the 96, and other models/years, one of the AC system parts which is known to leak/fail is the evaporator in the HVAC box in the dash. Hopefully this isn't your problem because not a fun job at all to remove the whole dash/HVAC box but a shop may charge you close to a grand if the evaporator needs replaced. Believe mine failed because the drain tube on the HVAC box was clogged causing the bottom of the evaporator to rot. Good thread around here on cleaning this drain line out. Good luck.

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post #17 of 49 Old 06-26-2013, 05:24 PM
coralman
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Lol dellis. Been there done that.

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Originally Posted by HighLonesome
lol...if life is as a simple as a 5.9 making you happy, I'd say go ahead and buy it on impulse. ZJs are the way of Zen. Wax on, wax off
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post #18 of 49 Old 06-27-2013, 06:18 PM
dusterdude
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Ac pro,baddest stuff on earth,you can get it at your local advance auto parts store
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post #19 of 49 Old 06-27-2013, 11:07 PM
dunkeye11
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Mine only cuts from the dash to defrost under accel over 2500rpm. Normal? Small leak?
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post #20 of 49 Old 06-28-2013, 12:13 AM
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Not normal under acceleration and you most likely do have a leak.
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post #21 of 49 Old 06-28-2013, 03:42 AM
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Or you may need to install a check valve. Its in the tsb's somewhere.

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Originally Posted by HighLonesome
lol...if life is as a simple as a 5.9 making you happy, I'd say go ahead and buy it on impulse. ZJs are the way of Zen. Wax on, wax off
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post #22 of 49 Old 04-22-2014, 08:01 PM
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I am currently addressing this myself. I am hoping to find and fix soon as Summer is just around the corner....
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post #23 of 49 Old 06-25-2014, 05:03 PM
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Vacuum T by heater hose and AC evap lines PLEASE

1998 jeep grand Cherokee Laredo 4x4 OK, I have this same issue, I got the AC cooling and the compressor running but now I need to fix the air location selector. Mine, the little vacuum tube off the T is just laying broke off the T next to the fire wall by the heater hoses where they pass through the firewall. I've read about having to remove the dash and I'm not beyond doing that but first I need to know where does the vacuum line off the T need to go to? Does it go to the back of the climate control air location selector? If that's the case I'll reroute and hook back into system with out removing the dash. I just don't know where it originally came from???? Thanks everyone.
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post #24 of 49 Old 06-25-2014, 05:44 PM
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post #25 of 49 Old 06-26-2014, 08:08 AM
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Ok So where is the original?

Quote:
Originally Posted by ZeeJay1997 View Post
it goes to the vent selector switch.
Does the original, before it broke, pass through the firewall at the heater hoses? Or the AC piping to the condenser or a hole somewhere in the firewall? I'm going to look for a "stub" before I reengineer. Thanks for the help.
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post #26 of 49 Old 06-26-2014, 02:25 PM
jeffjeep2
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would somebody be patient enought to show us where in the vent selector it should be attached? in my 98 GC, coming from the T at the engine bay, then through the firewall as it goes inside the cabin, its left hanging that is why i cannot direct the air infront. Pleasee need your help
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post #27 of 49 Old 06-26-2014, 04:09 PM
ZeeJay1997
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it will be the black line on the heater-A/C mode selector. it comes from the engine bay through the same hole as the a/c lines. some people have had success in fishing the line out through the hole and splicing it with a rubber hose.
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post #28 of 49 Old 06-26-2014, 04:30 PM
coralman
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pics might help

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Originally Posted by HighLonesome
lol...if life is as a simple as a 5.9 making you happy, I'd say go ahead and buy it on impulse. ZJs are the way of Zen. Wax on, wax off
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post #29 of 49 Old 06-26-2014, 07:57 PM
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Thanks

OK, thanks a ton fellows that gives me a much better idea where to look for this #$@!!@! thing.
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post #30 of 49 Old 06-30-2014, 12:49 AM
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Found it and working

OK, one issue down ten to go. I dug around the foam where the AC lines enter and found about 1/4 in of black Vac tube. I used a 2" piece of RC airplane, boat, car, etc fuel line and slipped over it as best I could where holding with a small needle nose pliers, I hooked the other end up to the broken line and what do you know!!
I know have cold AC from where ever I put the knob. I may try to put some regular vac hose or something over it but it's working and this stuff is pretty ridged but very flexible, it's made to hold up to liquid nitro methane, alcohol and oil so it may just be permanent. We'll see.
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