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  1. #1

    Default 94 suburban. front a/c perfect. rear a/c blowing heated air. HELP!

    so i got around to installing my a/c components. Got the new compressor, accumulator, pressure switch, and orifice tube in. Took to my friends home that has an a/c machine and got new freon and oil in there. front a/c is blowing frosty great!
    Now the issue is that the rear a/c is blowing heated air like if i have my heater on full blast. my friend told me it might be the expansion valve for the rear... any thoughts or input?

    *my rear controls do not have temperature control just blower speed. Also it is missing the knob so i use the front control to change blower speed.
    Last edited by 94burbtx; 07-14-2011 at 07:43 PM.

  2. #2


    Here's a pic if my pretty shiny new compressor. Anyone have any input on my rear ac issue? Haven't even looked yet cause of work and this beautifully scorching 105 weather were having here in Dallas.

  3. #3


    BUMP? tomorrow is my short day followed by my day off wed so i want to get this done. I was hoping for some input as ive never messed with a rear a/c... from what ive gathered its either the blender door or expansion valve...

  4. #4


    don't know about 94 model but maybe expansion valve. i just over hauled my 90 sub a/c and rear blew warm air ,had to discharge, replaced the valve and now blows cold .check to see if the line to the rear evaporator is cooling .do you have condensation from rear drain?maybe clogged valve or evap.hope this helps.

  5. #5


    thanks for the info. i bought an expansion valve but havent tried cause i dont have money for new freon until the 28th, 55+ hours at work and trying to get everything done for enlistment in the army.... anyhow i should get it done this friday. anything else i should be looking for while im poking around the rear a/c?

  6. #6
    Jr. Apprentice
    Join Date
    May 2011
    Kalamazoo, Michigan, United States


    X2 on the expansion valve the valve is open and not closing. get a new one. take it to your buddy if he has a machine suck the freon out and restall the freon back on the unit no loss of freon.

  7. #7


    +3 on the expansion valve is most likeley located in the right rear inside pannel..very S*** to get to and make shure to be very carefull with the unbolting it !
    U can get one on e-bay of at a part store..fairly cheap...also while u doing this , change the orfise tubes and vacum down the system before refilling it !

    Front and rear AC usually take about 45-50 PSI ont he high side at 2000 RPM !!!

    1996 Suburban K3500 SLT DUALLY
    1988 Camaro RS 383 stroker LT1
    1992 32' Aero-tek Race Boat, 600 CI BBC

  8. #8
    Jr. Apprentice
    Join Date
    May 2011
    Kalamazoo, Michigan, United States


    Bradenton is my home town i worked in Sarasota at auto radiator avanced auto air. when i was A/C tech we check air at idel about 600 ot 700 rpms. the low side 30-45 psi and high side no more that 300 about 250 is great no less than 200 so between 200- 300 psi.

  9. #9


    have you figured out your problem yet

  10. #10


    I'm in Dallas, too. It is too hot to not have A/C at the moment! Did you replace the parts?!?
    I like you.

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