99 bravada ac problem

my ac went out last summer took it in had freon added ran fine for a couple months and quit again. i was told that the evaporator core was bad. then another shop told me that if the core was bad it would not hold the freon. help me please. i can't seem to get a straight answer from anyone and can not afford to dump a ton of money on something that doesn't need to be fixed. any help/info would be greatly appreciated.

A good shop has a leak detector that can get real close to telling you where the leak is. Because you say it worked for a couple of months kinda indicates a leak. There are recharge kits with a seperate gauge included that lets you check the pressure yourself. It's best to purchase a repair manual for your year Bravada/Blazer at your favorite auto parts store and there's info with pictures to show you what you need to check if you're going to do it yourself.
Other than that, you'll need to let someone you trust fix your AC if you want it to work.

after reading some threads here i went out and looked behind the glove box. when the ac is on it takes a minute or so but a door opens up and the air blows very hot. could this contribute to the problem?

If you knew the AC compressor was running, what you describe could be a blender door problem.
There's a shiney aluminum tank under the hood on the passenger side of the engine bay of about 1 liter in size. If the AC compressor is running, this tank will get cold and sweat condensation. If it stays warm, the AC system is not working probably due to a leak.

Now, before I dig a hole I can't get out of, the USEPA says no to discharging refrigerant into the open air...it must be pulled out of a system with recycling equipment before opening any connections to make repairs. To just add enough refrigerant to get it going again does not repair the leak, is considered a discharge and is against USEPA rules.
If you have a shop repair it with a warranty, you'll be riding cool this summer.
You can also check with a local school for an automotive air conditioning class, then you can get certified to make repairs yourself.

the compressor is controled by a pressure switch in the freon line. if you are low on freon the compressor will not come on at all. if your compressor is running you have enough freon, look for other problems, such as the blender door. you can usualy tell if the compressor is coming on by the change in idle when you turn on and off the ac but you may need to watch the clutch while some one turns it on and off for you.

the shop manuals from the auto stores don't help much, just telling you its not user servicable and to take it to a professional, but the refill kits have pretty good instructions. some include a cd or a web site with complete instructions.

My rack books are pretty old...early 70's to mid 80's :cwm27:

i get what you are saying. "take it in to get fixed" its very frustrating going to all these shops and getting all different answers and paying for things and not having them be fixed. and these r recommended shops. do you know if it will hold freone at all if the evaporator core is bad?

The evaporator which is like a small radiator, can have a tiny crack or hole in it and still hold pressure for months but it'll still eventually leak out IF it has a tiny crack or hole in it.
The way they'll test for it is:
If the system does not have enough refrigerant to "satisfy" the low pressure switch, they'll add just enough refrigerant to get it going then they'll start looking for leaks. A leak in the evaporator will show up at the outlet vents with a high buck leak detector. It it comes up clean there. they'll check other areas like fitting connections or behind the compressor. If a leak is found, they'll take the refrigerant back out then let you know what repairs are required. If they put in 2 lbs. of refrigerant in for the test and was only able to pull 1 lb. back out due to a leak, you'll be charged for that pound of lost refrigerant which is only right...why should they have to eat 1lb. refrigerant that leaked out of a customers car.
If there was some already in it, just not enough to click off the low pressure switch, it'll have to be removed to make repairs. If you choose not to make those repairs, they can't put any back in because it'll then be an ill-legal discharge to the atmostphere by the local state and federal rules with fines up to $20,000, loss of certification and possible jail time for the shop owner.
You can always check with the Better Business Bureau for crooks.
Back in 1974, I didn't want a car with AC...it stole horsepower.

thank you for all the information. i would like to ask 1 more thing and that is where is the blender door? compressor comes on that is not a problem at all. i just want to do a process of elimination on my part. again i door appreciate all the info. it has been very helpful.

Sorry, not having replaced any, I searched.

Thanks to wlfowler29

" I don't know if anyone will check this thread but I thought I would add my two cents. I have the same problem on a 98 blazer. The blend door actuator is on top of the heater case behind the glovebox. You don't have to take the dash out to get at it. There is a little metal tab close to the latch. Push it and the glovebox door will swing down. There is a vacuum actuater that is immediately visible. The actuator is behind it. It only has two screws that you can see so don't waste time feeling in the back for a third screw. At least Chevy did something right. I have replaced the climate control computer and this was not the problem. My blend door actuator is on its last legs but it is not the problem either. For some reason it is getting the signal to hold the door open towards the heater core and I have not found why."