GM Truck Club
THE PREMIER CHEVY TRUCK & SUV FORUM
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Page 1 of 2 12 Last Post byLast Post by
Results 1 to 10 of 13

Thread: Dead A/C

  1. #1

    Default Dead A/C

    Ok, so my I bought my truck knowing that the A/C doesn't work , but I'm taking a trip to TX next month and I need it!

    My first thought was to check the freon levels, they were slightly low, but not empty, so I filled it up. No go. I filled the system with freon to the higher levels of the tolerance and still no go, but something did happen when I did this: The compressor started to engage and disengage every couple of seconds, previously, it had not engaged at all. When it engages, the pressure drops way down, then the pressure shoots way up when it disengages. Is the constant engage/disengage normal? Perhaps this is what the problem with the A/C is?

    I've checked the pressure levels through out the day yesterday and today, and have seen no drop in pressure, so I'm ruling out leakages. Maybe the canister needs more freon oil?

    Any suggestions are appreciated. My Haynes manual says to take it to the shop
    Scott

    ΜΟΛΩΝ ΛΑΒΕ

    '94 Chevy Suburban K1500
    3" exhaust w/ aero turbine non-baffled muffler
    CFM Technologies TB spacer
    CB w/ 44" whip antenna


  2. #2

    Default

    these are simple if you break the system down.
    yes the compressor should kick in and out farly often.
    you checked the level and it is good. can you feel one AC line getting cold or see it sweat? if so then the freon is cycling if not you might have a plug somewhere.
    now if the flow is flowing then your heator / blend door motor is not moving to allow the cool air in. test the motor and or replace.
    you do hear the fan motor running correct?
    mike
    Michael Collins
    1993 4X4 Suburban
    many other toys as well

  3. #3

    Default

    Quote Originally Posted by collinsperformance View Post
    these are simple if you break the system down.
    yes the compressor should kick in and out farly often.
    you checked the level and it is good. can you feel one AC line getting cold or see it sweat? if so then the freon is cycling if not you might have a plug somewhere.
    now if the flow is flowing then your heator / blend door motor is not moving to allow the cool air in. test the motor and or replace.
    you do hear the fan motor running correct?
    mike
    From what you're saying, it sounds like a clog. None of the lines get colder or create condensation on them.

    I'm fairly fure the blend door is fine, when I turn the heat all the way up I can definitely feel the difference. And the fan motor seems to work fine at all adjustment points between low and high.

    Guess it's time to take it to someone to have it looked at.

  4. #4

    Default

    You want the low pressure side to stay between 40-46 psi when the compressor is engaged. There is a low pressure switch that cuts the compressor off when the pressure gets below 20 or so psi. Set the a/c to max, cold and high fan and fill until it will hold steady while engaged. The high side should be in the 250 +/- range.

    Don't worry about needing an a/c here in Texas, it was a nice cool 107 at my house yesterday. The hot weather won't be here until late August.
    Gary

    99 K 1500 Suburban
    78 Silverado Big 10 w/factory 454
    00 S-10 Blazer
    1976 Trans Am
    1980 Honda CB900 Custom

  5. #5

    Default

    Quote Originally Posted by GaryL View Post
    You want the low pressure side to stay between 40-46 psi when the compressor is engaged. There is a low pressure switch that cuts the compressor off when the pressure gets below 20 or so psi. Set the a/c to max, cold and high fan and fill until it will hold steady while engaged. The high side should be in the 250 +/- range.

    Don't worry about needing an a/c here in Texas, it was a nice cool 107 at my house yesterday. The hot weather won't be here until late August.
    Oh hell, I'm a Colorado boy born and raised. I get uncomfortable when temps reach the 80's. 100+ is a killer for me.

  6. #6

    Default

    Quote Originally Posted by GaryL View Post
    You want the low pressure side to stay between 40-46 psi when the compressor is engaged. There is a low pressure switch that cuts the compressor off when the pressure gets below 20 or so psi. Set the a/c to max, cold and high fan and fill until it will hold steady while engaged. The high side should be in the 250 +/- range.
    Excellent information. I'm always just eyeballing the pressures without knowing exactly where I should be... I just watched the pressures to make sure it wouldn't take anymore and the air coming out was cold...oops..
    Christopher

    1991 Chevy Suburban 1/2 ton 2WD w/ chevy SBC 350-3/4 ton drivetrain upgrade w/4.10 gears 200K miles
    2005 Saturn ION-2 Stock 277K miles
    1982 Bronco, 1993 Bronco (sold), 1971 M35A2 Deuce and a Half



    There are 10 kinds of people, those who understand binary, and those who dont...

    Remember kids, the only difference between screwing around and science is writing it down- Adam Savage

  7. #7

    Default

    Gary, thanks for the tips and info. I went out and looked at the pressure again, and while the pressure was high without the compressor on, it dropped to ~25psi when it was engaged. Put some more freon in and I've got cool air! Not quite cold and it looks like I'll need another bottle, so hopefully this takes care of it.

  8. #8

    Default

    Great news!! Where are you going in Texas?

  9. #9

    Default

    We're leaving Denver the night of the 17th of Aug. (Sunday) and will stop in Amarillo on Monday. Then Tuesday night we'll be leaving Amarillo and heading for Dallas for a few days then turning around and making the same trip with a couple of days in Amarillo. Wife has family in both cities.

  10. #10

    Default

    When you come through Lewisville on I-35E, you'll be about 13 miles from me, be sure and wave.

Page 1 of 2 12 Last Post byLast Post by

Similar Threads

  1. My DRL's are dead
    By Mean_Green_95 in forum GM Electrical Tech
    Replies: 18
    Last: 01-12-2010, 11:27 AM
  2. dead battery !
    By loic in forum Chevy Tahoe Forum (GMC Yukon, Cadillac Escalade)
    Replies: 7
    Last: 08-31-2009, 07:01 PM
  3. Dead Battery
    By starultra in forum Chevy Tahoe Forum (GMC Yukon, Cadillac Escalade)
    Replies: 2
    Last: 02-22-2009, 06:23 PM
  4. dead radio on acc
    By Jadams805 in forum Audio, Video & Gadget Tech
    Replies: 0
    Last: 02-17-2009, 09:21 AM
  5. 96 suburban dead
    By meenkeene518 in forum General Chevy & GM Tech Questions
    Replies: 6
    Last: 01-19-2009, 08:56 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •