whats wrong with my a/c??

Question

I just bought a 1999 GMC Jimmy and i need help figuring out whats wrong with the a/c. I turn it on but the air isnt cool. The heater seems to be working fine. The previous owner has had it recharged before, but it only lasted 2 weeks and the mechanic said that there was no leaks. Just curious if anyone can tell me what could possibly be wrong and maybe how much it would cost to fix it.

Answer 1

it is broke thats whats wrong. you have a bad leak in the system and depending where it is it can be cheap to very expensive.

Answer 2

Using a refrigerant leak detector is a relatively simple exercise, but a few tips can make it far simpler. If your car’s air conditioner is just not blowing as cold as it used to and you have had your system recharged with Freon recently, you may have a leak. The first order of business is to locate and find it. One of the best and easiest to use tools is a refrigerant leak detector. This handy little device can sniff out the leaking refrigerant and give off an audible alarm to tell where the gas is escaping.
Once you turn on the refrigerant leak detector, its time to begin your search. Start with holding the sensing tip as close as you can to the air conditioner components and move the tip at about 2 inches per second. Move the tip under the tubing and check carefully around bends, especially fittings. Remember refrigerant is heavier than air and sinks to the ground. So it is best to check under tubing and the lower areas of the A/C system. When you first start to scan the area, set your refrigerant leak detector to the least sensitive setting. After the alarm begins to sound, you are getting close. Now begin to adjust the sensitivity to higher settings to really pinpoint the source of the leak. You may have to use a soap solution to find exactly where the leak is once the area is pin pointed with the leak detector.
What do you do if you have gone through the whole air conditioning system and still cannot locate the refrigerant leak? First make sure you are in a relatively closed off environment, like an auto shop or your garage. Wind may be blowing the refrigerant away from the car and make it impossible for the refrigerant leak detector to get a lock on the source. Another problem you may have is finding the general area but there is not enough refrigerant being expelled to really nail down the leak. In that case, you can try wrapping the area with some type of plastic wrap and let the Freon accumulate. After you take the wrapping off, enough refrigerant should have gathered. If you find more than one leak or suspect it, fix the larger leak first and then look for the smaller ones.
If you still cannot find the leak, your refrigerant leak detector may need to be cleaned. The sensing tip of the probe is the most sensitive part of the unit and after time it may become clogged with dirt, grease, and oil. Inspect the tip for dirt. If it looks dirty to the naked eye, it probably cannot get a good reading. The sensing tip can be cleaned with almost any vaporizable solvents. We would recommend a simple, denatured alcohol. Warm, soapy water is also a good back up choice if nothing else is available. After washing the tip, allow it to dry completely before attempting another scan.
Using a refrigerant leak detector is a relatively simple exercise and can save you time and money on expensive car air conditioning repairs. Also, the latest EPA rules require service technicians to repair any excessive refrigerant leaks they discover in air conditioners. The old days of buying a can of R12 at the local auto parts store to top you’re A/C are long over.

Answer 3

With engine off, jump 12V to the compressor clutch to see if it clicks in. If so, then w/engine running, jumper in place, see if blows cold, if yes there is probably a bad sensor or loose connection, trace back from compressor, look for voltage at high & low pressure switches. If you have a sight glass in the system this will give you a chance to look for foam &/or bubbles, indicating low; clear is either full charged or empty. Also look around all system parts for oil which would point to a leak. Loss of a can or so a year is not uncommon.
If no cold air, it's probably low on freon, if it is R-12, get a kit & convert it to the cheap 134, [it's just a matter of evacuating, screw on adaptor fittings, recharge]. A 134 system is easy to add refrigerant to, just be sure to use the service valve under the BLUE cap, fully read the instructions w/the kit.
If compressor clutch does not pull in w/12V, there is the problem.
Never throw parts at a problem. DIAGNOSE FIRST. Either work with a shop manual or take it to a reputable shop. A/C systems can be dangerous to work on, so do not approach this lightly!

Answer 4

first you need to check if the compressor is running. if not then you need to trace the electrical circuit backwards to find the problem. start with the ground, then the connector itself. the next item is the pressure switch. sometimes these switches go bad and dont close the circuit. bypass the switch, and if the ac runs, that is your problem, if not then check the wiring and the inside switch. if the electrical checks out, then have the system pressures checked to make sure they are where they should be. i know the mechanic said there was no leaks, but did he run a dye into the system to check for leaks? or did he use another method. the dye will tell you for sure yes or no leaks.

Answer 5

Since you report the A/C was working after it was charged, the most obvious problem is that the refrigerant is indeed leaking out. Sometimes the leak is not in an obvious place, such as with the evaporator under the dashboard. Heaters use entirely different operating hardware. The only time the heater and A/C come together is on the dashboard temperature control module.

Answer 6

If the system is still fully charged you could have several problems. One is whats called the black death. Its a black buildup of decomposing coolant in the lines. Another is a seizing compressor, and the last is a bad pressure switch. Check your fuses also, as the compressor circuit is fused. Go to the link below and do some research, there is a lot of info there. Repairing an auto AC system is a BIG job, thats why it costs so much.

Answer 7

Take a look at the compressor, is it turning? I'm talking about the center section of the compressor. Did the mechanic put a set of gauges on the AC lines. It is possible that the thing was overcharged too. With the summer coming on, take it to a repair shop and get it fixed. Good luck.

Answer 8

could be that the Freon is low or the compressor clutch is not working turn the air on lift up the hood and check to see if the clutch is working if it is not then the Freon could be low.hope this helps.

Answer 9

your a/c system does have a leak somewhere if it only lasts 2 weeks have someone do a vacume test or a dye test on it vacume is usually cheaper but the dye test is faster and can pinpoint the smallest leaks which you must hane since it lasts for two weeks.