1999 gmc suburban ac problems?

[dixy]

my ac was getting warmer in the front of the burb but the back was blowing really cold, now its starting to blow warmer too. Is there something that it could be besides the compressor? and any ideas on how I can fix it?

 

[repo2agent]

going through the same problem with my tahoe. I have heard there is some type of valve in the rear ac lines that might be bad.
i would take of the rear panel to make sure or to see whats working like the temp control door that switches from hot to cold

 

[johncondo2001]

I had a spider web in one the lines

 

[dennis0851@sbcglobal.net]

there is an expansion valve in the rear a/c unit. it is possible that it may be plugged. as the others mentioned it just may need recharging. if you are mechanically challenged, and i dont mean that as an insult, take it to a qualified a/c tech to get the problem repaired

 

[dark_desparado66]

you've got a burb too, sweet.
not sure if your model has a cabin air filter but if it does it may be time to check it. a cabin air filter filters out all incoming air before it enters the cabin. if this gets clogged it will reduce the amount of airflow going through your front evaporator. your rear unit does not draw air from the outside, hence it does not have a filter. so that's gonna blow cold as long as the refrigerant lasts.
another possibility is your front evaporator is clogged, be it leaves or bugs all this CAN get sucked into your burb. first thing it hits is gonna be your evaporator. or if you have your heat on it will hit the heater core first.

start checking the small things first: cabin air (if equipped)
refrigerant level (gauges found at most local auto parts stores) follow the directions on the gauge some ask that the vehicle be running some don't. if its low refill it. using R-134a your capacity should you need it is 57 oz

after that, if you feel comfortable ripping your dash apart you can check to see if your evaporator is clogged.
this step may best be left to a pro as they have insurance to cover any damage they cause and the tools to do the job right.

 

[The_Benster!]

Try hitting it. That always workd for our 98 Dodge Caravan.

 

[bskowal]

I had the same problem a year ago. As it turned out a leak developed in the line where it runs though the firewall. Most likely from rubbing on the firewall steel. It was a slow leak that would leak only under high pressure, so it took a while. Each time I'd loose the front A/C first, then eventually the rear A/C. Charging the system yourself is easy if you have the set of gages. It does take an hour or so, so give yourself some time and have 4 cans of R-134a to start.