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

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by 94burbtx, Jul 14, 2011.

  1. 94burbtx

    94burbtx New Member

    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: Jul 14, 2011
  2. 94burbtx

    94burbtx New Member

    Here's a pic if my pretty shiny new compressor. [​IMG]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. 94burbtx

    94burbtx New Member

    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. scruffiest1

    scruffiest1 New Member

    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. 94burbtx

    94burbtx New Member

    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. 66impala

    66impala New Member

    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. DAREDEVIL

    DAREDEVIL New Member

    +3 on the expansion valve ..it 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 !!!
  8. 66impala

    66impala New Member

    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. caddy_sonoma92

    caddy_sonoma92 New Member

    have you figured out your problem yet
  10. janikphoto

    janikphoto New Member

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

    BobEhud New Member

    okay
    1. Expansion valves don't open or close but are a restriction allowing the liquid freon to convert to a gaseous state.
    2. If your have rear heat AND rear air which im sure you do could be as simple as the blend door will not close off the rear heat,which would account for cold
    up front warm in the rear.Hell get a chiltons find out where is at and ck..some zip ties till winter
    3. Everyone could be right could be a clogged expansion valve but if that is the case your low side pressures should be way off. Whats the ambient temp and
    what type of pressure are you getting on the low side.This pressure may take a sec or two you have a lot of AC line in that set up.
  12. janikphoto

    janikphoto New Member

    For those of you who haven't studied up on a/c before, this is correct. It is the part that creates more or less restriction for the freon at the point it changes from liquid to gas. However, they are known for being a weak point in a/c systems, as they can get easily clogged.

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