AC Problem - HELP

[krwyellowZ28]

I'm having problems with the HVAC system in my 2000 GMC. For the longest time I thought my AC had a leak and was out of freon. I got tired of sweating on my way to work last week so I decided to do some trouble shooting.

With the AC on full blast I check the pressure and to my surprise it was right in the operating zone, and within a min or two the condensor was sweating like crazy and cold to the touch, so apparently I'm good on that end. Now, I had noticed the knob for adjusting the temp of the air didn't seem to do much (it was always hot air coming out of the vents), so i put my switch pannel into an '02 Z71 and it operated like it should.

So now I'm thinking that the door, actuator, or any one of several parts in the exploded view of parts on gmpartsdirect.com catologue could be the culprit. Has anyone had their heater box apart to know what mechancal malfunction could cause this? I would have to think it's an actuator, servo motor, or something along those lines. Any help on this would be great... no AC is killing me!

[GasGuzzler]

The condenser should be hot. It's in front of the radiator.

I think you mean accumulator....it's on the firewall and since it's in the low side, it should be cold and sweaty LOL.

Most likely you have a temperature actuator out but the 99-2002 manual systems don't store codes.

Pull the panel off the bottom of the RH side under the dash. The temp actuator is just right of center on the bottom of the case. Put your finger on the shaft in the middle and feel if it moves when you change the temp knob. If not, it's probably bad. Unplug it then remove the two 5.5mm bolts holding it on. Rotate the shaft by hand and feel for a temp change. If it does, put a new actuator on.

If the shaft and door move the actuator is good and you'll need low and high side pressure readings. Don't trust those cheesy parts store charge gauges.

[krwyellowZ28]

The condenser should be hot. It's in front of the radiator.

I think you mean accumulator....it's on the firewall and since it's in the low side, it should be cold and sweaty LOL.

I knew that...

Most likely you have a temperature actuator out but the 99-2002 manual systems don't store codes.

Pull the panel off the bottom of the RH side under the dash. The temp actuator is just right of center on the bottom of the case. Put your finger on the shaft in the middle and feel if it moves when you change the temp knob. If not, it's probably bad. Unplug it then remove the two 5.5mm bolts holding it on. Rotate the shaft by hand and feel for a temp change. If it does, put a new actuator on.

If the shaft and door move the actuator is good and you'll need low and high side pressure readings. Don't trust those cheesy parts store charge gauges.

Thanks!! That's exactly the kinda of info I was looking for. Thanks for the fast reply, too.

[jetersaurous]

I have the same problem!!! The pressure is right, the compressor kicks on and the smaller pipe is colder than the larger one like it should be. BUT NO COLD AIR!!!

[GasGuzzler]

Thanks for the reminder for the following disclaimer...

DO NOT PLUG IN THE ACTUATOR ELECTRICALLY WITHOUT IT MATED TO THE TEMP DOOR AND BOLTED UP SECURELY.

It will over-travel and die.

[krwyellowZ28]

The temperature actuator was the problem. It kinda makes me mad I went this long without AC for a $70 part and a few hrs of effort just because I'm hesitant of messing with the HVAC system.

Oh well, she's back together with cold AC

[GasGuzzler]

Be glad it's not an 03+ as those acuators are $197 and the one of the passenger side on those is not fun for a novice.



Just ask budfan...Alton, you there?