AC not working

[draconianruler]

My AC is not blowing cold air. I checked the fuses and they are fine. How can I tell if the compressor is being engaged or not? The belt moves around the compressor pulley but it doesn't seem anything else on the compressor is moving. Is that normal or is my compressor bad?

[IRA51]

You can see the end of the compressor spin if it is working . try haveing a friend turn on the ac while you watch the compressor. you will see and hear it engage if it works . If it won't go on it could be low on freon ,or the high preasure switch or connection to the high preasure switch could be bad . Or your ac head unit in the dash took a dump . Any ac shop can tell you whats wrong free ,fixing it will cost though .Good luck and be glad your not in Phoenix with out AC in the summer .

[draconianruler]

I just bought some freon and I'll try charging it. Hopefully that is the problem.

[draconianruler]

Does the Hummer use a special AC fill adaptor? When I connect the Freon can to the fill nozzel (smaller one), I get no pressure. If I squeeze the trigger to add nothing comes out. The conncection seems to be connected perfect. I checked by connecting and adding a little on my vette and it works. Am I doing something wrong?

[IRA51]

NO. THERE IS A HIGH SIDE AND A LOW SIDE PORT. FYI if you over charge the system you drive the head preasure up and blow the seals in the compressor ,be carefull . Have a good AC tec check the system for you . An over charged system will not get as cold as a properly charged system.

[draconianruler]

So it turns out you need a special adaptor to connect the pressure gauge/hose to the new refridgerant bottle. Apparently if you have a older pressure gauge/hose it will not work with the newer bottles (It might just be a CA thing).

The good news is that my compressor and AC does work when the refridgerant is full. The bad news is that I have a bad leak somewhere. After a day its all empty.

I bought some more refridgerant with the UV dye and looked for the leak but can't find it. You'd think it would be easy to find with such a bad leak. The only place I didn't check was the evaporator area inside the dash. Anyone ever pull out the dash to get to the evaporator core?

[IRA51]

WITH GM vehicles it is very rarely the evap core, check the condenser for impact damage. GM compressors leak at the front seal a lot .

[draconianruler]

Originally Posted by IRA51

WITH GM vehicles it is very rarely the evap core, check the condenser for impact damage. GM compressors leak at the front seal a lot .

I had checked the condenser and traced the lines and no leak (at least that I can see with the UV dye). I'll double check everything this weekend again before going into the dash.

[Bimmer9938]

Usually they have a sensor that will shut off the condenser if the refrigerant is low or gone (so it doesn't burn out), remember to have the system pressured down before charging or you will have moisture in the system which can cause a blockage. Pay some money to have this done properly as you want to keep the high and low sides even. Using a dye in the refrigerant will help detect leaks as well. It's also a good idea to pressure down the system then replace the schrader valves on both high and low sides as they can cause a leak as they age as well.

[draconianruler]

Finally broke down and bought an electronic halogen leak detector and took apart most of the front trims. Just as I feared, my evaporator core is leaking somewhere. I removed most of the trim to be able to crack open the cover of the HVAC unit where the evaporator unit is. A/C leak detector goes crazy. Argh......looking at the directions to replace evaporator seems like I have to remove EVERYTHING in the front. I feel like crying Why couldn't it be something easy like the compressor.

Any suggestions on how to replace the evaporator without having to rip apart the interior and removing the HVAC unit?

[Bimmer9938]

http://stores.homestead.com/KwanChiK...lug/Detail.bok