Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

vent/defrost/heater????

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by coolhandluke, Dec 18, 2001.

  1. coolhandluke

    coolhandluke 1/2 ton status

    Joined:
    Oct 23, 2001
    Posts:
    116
    Likes Received:
    0
    Location:
    Dallas Texas
    what controls where the air comes out, and where is this unit?

    I took off the dash, and see the unit that moves when you slide the lever, and wires going off from it, but can't follow the wires to whatever they lead to. WHere is it?

    Right now air comes out all 3 places equally regardless of where the lever is, what could cause this?

    83 k5 originally diesel, now 350, 700-R4 12 bolt rear, 33x12.50 BFG Trails (yuck), desperately seeking a lift
    sometimes nothing is a real cool hand
     
  2. MOABDADC22

    MOABDADC22 1/2 ton status

    Joined:
    Jul 24, 2001
    Posts:
    1,348
    Likes Received:
    0
    Location:
    Cheyenne, Wy
    Those aren't wires, they are vaccum lines. Check to see that one of them is not kinked.

    <a target="_blank" href=http://www.moabdadc22.alloffroad.com/>http://www.moabdadc22.alloffroad.com/</a>Real four wheelers don't need tools to remove body panels, paint, tail lights..etc.
     
  3. coolhandluke

    coolhandluke 1/2 ton status

    Joined:
    Oct 23, 2001
    Posts:
    116
    Likes Received:
    0
    Location:
    Dallas Texas
    where do the vacuum lines lead to?

    83 k5 originally diesel, now 350, 700-R4 12 bolt rear, 33x12.50 BFG Trails (yuck), desperately seeking a lift
    sometimes nothing is a real cool hand
     
  4. 1975k5

    1975k5 Registered Member

    Joined:
    Feb 28, 2001
    Posts:
    44
    Likes Received:
    0
    Location:
    Alabama
    the source is a vacuum canister on the firewall to the right of the heater box. It will look like a black ball that has been flattened(at least my 75 looks this way) and SHOULD have vacuum lines running to and from it. My 75 did not have a vacuum line running to it when I purchased the thing and it drove me crazy until I ran a source to it and it works like a champ.

    Hope this helps

    Tom
     
  5. prjt_blzr

    prjt_blzr 1/2 ton status

    Joined:
    Mar 4, 2001
    Posts:
    352
    Likes Received:
    0
    Location:
    COS, CO
    This is a common problem on GMs. Usually the culprit is the door that directs the airflow. There is a small plastic bracket that breaks and does not allow the door to open or close fully. This door is located just to the left of the glovebox behind the lower dash. If you remove the glove box, you will see a plastic duct that bolts to the heater box. Remove the two lower 5/16 screws and the upper screw to remove this. You will then see the door with a plastic bracket. If you run the truck and change the airflow from vent/defrost/heater you will see the bracket move. Make a new bracket out of sheet metal and you will be good to go.
     
  6. coolhandluke

    coolhandluke 1/2 ton status

    Joined:
    Oct 23, 2001
    Posts:
    116
    Likes Received:
    0
    Location:
    Dallas Texas
    actually, my problem is that there is no vacuum canister at all!

    :(

    83 k5 originally diesel, now 350, 700-R4 12 bolt rear, 33x12.50 BFG Trails (yuck), desperately seeking a lift
    sometimes nothing is a real cool hand
     

Share This Page