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A/C, defroster not working

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 90K5, Mar 28, 2001.

  1. 90K5

    90K5 1/2 ton status

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    My A/C and defroster are not working any more, the heater barely works, I can only feel heat if I put my hand right next to the vent...anyone know what's wrong with it?

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  2. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    There some vac-lines running off your switch unit that control little doors to a unit on the passenger side that directs airflow. If you've got everything going out I'd say its probably your switching unit.

    [​IMG]
     
  3. 90K5

    90K5 1/2 ton status

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    Any more opinions?

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  4. NewK5Guy

    NewK5Guy 1/2 ton status

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    When you put the motor speed on high, is the motor turning? I'll assume the blower motor is still working. If so, I'd check the vacuum connections. Somewhere a vaccum line has come apart. I know all about this. I just restored the vacuum system on my diesel Jimmy. Your vacuum ball should be on the passenger side fire wall, right above the blower motor, at least, that's where it is in my 84 k5. Can't miss it. Both lines attached on the bottom? If so, trace the big one. That's the source line. Follow it and anything it's attached to. Eventually you'll find the problem.
     
  5. 90K5

    90K5 1/2 ton status

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    Will I hear the blower motor turning? I that legal for me to fix?

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  6. NewK5Guy

    NewK5Guy 1/2 ton status

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    I hope that's a joke, cause I don't get it. The blower motor. You know, the motor and fan that pushes the air through your vents? When you put the selector on hi, is it turning?
     
  7. 90K5

    90K5 1/2 ton status

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    Oh...no its not.....sorry wasn't thinking there...

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  8. Derf00

    Derf00 1/2 ton status

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    I recently did a heater core replacement and in the process found that there is a door that is phneumatically controlled that directs the heated or cooled air up or down had a broken control arm that attaches directly to the door. If you take out your glove box, you can move your heater and A/C controls and see if they are working properly. The upper control lever controls the A/C - Vent -Heat - Defrost and is phneumatic, the lower lever controls the temp and is manual. Sounds like you might have a blower motor also.

    Derf00
    http://www.derf00.coloradok5.com
     
  9. NewK5Guy

    NewK5Guy 1/2 ton status

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    Could have some resistors burned out keeping the motor from turning at full tilt.
    I'd take it to a mechanic and have it diagnosed. It shouldn't cost much.
     
  10. DMK

    DMK 1/2 ton status

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    F.Y.I.The resistor is for low and medium speeds. If resistor is bad fan will only run on high. Does the blower work at all?
     
  11. 90K5

    90K5 1/2 ton status

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    blower does not work at all. I"m gonna look at it in a couple minutes.

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  12. prjt_blzr

    prjt_blzr 1/2 ton status

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    If the fan is not turning at all verify that the blower motor has not blown the fuse or the fusible link. Follow the large red wire from the relay next to the blower motor back to power connection on the firewall. There should be an in line fuse or a fusible link that is toast. Also check the ground wire from the frame of the blower motor to the body ground.
     
  13. 90K5

    90K5 1/2 ton status

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    HELL YES!!!!!!! I posted that and went out there to look at it....the ground wire was disconnected. She cools like a dream now...or at least good enough

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  14. bigblue

    bigblue 1/2 ton status

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    That is funny, the same thing happened to me. I just plugged in the wire and the defrost work good as new. My AC doesnt't work though...later

    baja surf nazi -...A late storm NEVER comes...

    [​IMG]
     

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