AC PROBLEMS

Did you try pulling the hvac fuses to reset the system. I believe there are videos of the reset process

2011SSVHOE said:

Did you try pulling the hvac fuses to reset the system. I believe there are videos of the reset process

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I actually did take a look in the fuse box to make sure the fuse was ok, there was a little dead mouse in there with a couple pieces of cat food. So glad nothing bad happened i didn't even know it was in there.


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kwOH said:

I actually did take a look in the fuse box to make sure the fuse was ok, there was a little dead mouse in there with a couple pieces of cat food. So glad nothing bad happened i didn't even know it was in there.


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Start following your wires then. If a mouse is dead in your fuse box, I'd be willing to bet he's chewed on a wire or two under your hood.


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Well im going to hope for the best and go from there, that falls under the "shit happens" category, i don't think the ac problem is electrical related, I'm beginning to think its more orifice tube related. Actuators seem to be working fine, I am getting some noises now, sounds like a circulation issue.


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I am by far technical in this area, but just addressed my AC issue. I know when I topped off my AC, it didn't really fix the problem. When I used my mechanics AC pump and evacuated the system and then recharged it worked fine. 1 month later, I was at it all over again, but had put die in the system when tackle the month earlier. At that time, my AC would run warm up front and cool in back. Needless to say, I had a leak in my condenser and hi/lo pressure lines at the rear evaporator. Since the lines are a bigger job and costly, I decided to just tackle the condenser. While I was in there I also replaced the accumulator and orifice. The original orifice looked good as new. Well 2 months later and my AC is strong, but I know at some point I will need to address the rear-seat evaporator issue. The lines were leaking just before and at the mounts to the rear evaporator (all rusted/corroded up).
Again, there are many other AC issues you can address, but starting with some dye would be a good idea if not for future potential AC issues. My experience also suggests to always evacuate the system but for refilling/topping off. Just my 2 cents.
2005 Tahoe LT with rear HVAC.

Johnb21 said:

I am by far technical in this area, but just addressed my AC issue. I know when I topped off my AC, it didn't really fix the problem. When I used my mechanics AC pump and evacuated the system and then recharged it worked fine. 1 month later, I was at it all over again, but had put die in the system when tackle the month earlier. At that time, my AC would run warm up front and cool in back. Needless to say, I had a leak in my condenser and hi/lo pressure lines at the rear evaporator. Since the lines are a bigger job and costly, I decided to just tackle the condenser. While I was in there I also replaced the accumulator and orifice. The original orifice looked good as new. Well 2 months later and my AC is strong, but I know at some point I will need to address the rear-seat evaporator issue. The lines were leaking just before and at the mounts to the rear evaporator (all rusted/corroded up).
Again, there are many other AC issues you can address, but starting with some dye would be a good idea if not for future potential AC issues. My experience also suggests to always evacuate the system but for refilling/topping off. Just my 2 cents.
2005 Tahoe LT with rear HVAC.

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Yes... what johnb21 said. I have an 03 Tahoe and I replaced actuators, recharged, new ambient temp sensors, reset the system... nothing worked. Finally put dye in the system and it took about 2 minutes before I saw a highliter yellow puddle on the ground under the back of my tahoe. My rear condenser had a leak and it was sitting in a pool of that yellow dye. Long story short, dont just jump on the actuator bandwaggon. I did and it cost me $$$ for no reason. Found out later you can check those before you buy new ones. Just pull them out, leave them plugged up and adjust the temp all the way up and down and see if it moves. I'm not saying that's not the problem, it could be, but I would get some dye and see if it leaks first. It's the easiest thing to do.

Ok, you should NEVER use those parts store recharge deals, a joke at best, with 134 you MUST have the exact amount by weight not by pressures as in the past with R12. also had mine start screwing up and was the blend air door motor, right side dash next to console, not bad to change once you get the one pain in the ass screw out from lower cover. you can also try a reset of all the motors, disconnect battery for a min, turn ign on, do not start, and let the system reset.

kwOH - I think you're right on the $ with a 'flow' issue. Pop your hood with the A/C on and check to see if your condenser is sweating. If the evaporator behind the dash is clogged you'll be able to tell by feeling the tube leading from the firewall into the top of your condenser isn't cold.

Its going to end up going in the shop eventually, the air isnt blowing 100% hot, its still cold just not performing like my crew cab or how it originally was. Ill post what cures it, more than likely it will just need $. Lol


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kwOH said:

So I went out and jumped in the nnbs yukon today, 95 degrees out, and the air starts actin up on me all of a sudden, its blowing warm air from the front vents and a little cooler thru the rear, tried to recharge it and tue gauge says its full. Suggestion on what to check next??

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Let's start with "tried to recharge it and tue gauge says its full." What does that mean in your language?

Refrigerant is strange stuff unless you really understand the concepts of Air Conditioning. Starting with, if there is one drop of liquid refrigerant in the system it will read full rest pressure (approximately equal to ambient air temp). The ONLY way to know if a system is really full is to evacuate and put in a full charge.

Running pressures are very different with the high side being in the 275 to 300 psi range on a 95 degree day, the low side somewhere around 50-55psi.

The better way to get an idea about the state of charge in the system is the lowest tech process, but it works.... with the system running, feel the metal lines. Temperature roughly equals pressure. The small diameter lines are the high side and should be quite hot to the touch (remember 275 - 300 psi = the same in degrees). The large diameter lines should be cool/cold (50-55 degrees). If that's happening the AC System is operating properly.

As far as the rear AC vs front, the two systems are separate systems sharing a compressor, accumulator and condensor. The front can be cooling fine while the rear isn't cooling.

Do the touch test back by the rear evaporator, remember two different size lines. You should be able to feel some difference even on the rubber hoses. If the rear evaporator is getting cold, it's not refrigerant issue, now you need to look at air flow issues. The blend doors (directing air over the evaporator when called for) are controlled by the BCM so you need to be able to interface with it. It's not an on/off situation, it's steps on the control motor so you need to have a bit more than the code reader.

DIY AC repair is pretty much a fools errand, unless you have a complete understanding of refrigeration principles you're just tossing money at the problem. You then must have a means of completely evacuating the system and measuring the amount of refrigerant and oil going into the system. That calls for expensive equipment that you aren't going to be using very often.

You need to be able to diagnose which component is malfunctioning and to be able to check your work to assure that it's gas tight. It get pricey in a hurry.

Sometimes you just need to bite the bullet, take it to a qualified technician, ask lots of questions and make your best call. Yeah I know we all wish we were back in the 1970s when repair time comes around, but we love the 2000s technology when everything is working right.