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Adjusting heating controls

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by smack, Jun 19, 2000.

  1. smack

    smack 1/2 ton status

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    I'm about to partake the bewildering task of fixing my air-conditioning. The question I have is this:
    My cold/hot air lever does not slide all the way over to the left (it stops about 3/4's of the way). About a year ago I ripped apart my air distributor to replace the heater core and now I'm wondering if I put it all back together wrong. Basically, there's a revolving door within the distributor that diverts air either up into the defrost or down to the floor. My defroster does work and when I put it on heat it does blow out the bottom. Maybe the rod that connects the hot/cold lever could be out-of-adjustment? One-other thing, even though the A/C doesn't work, when I put it on max or normal it definately does not blow out of the dash vents. Does the hot/cold lever control where air gets diverted or is it just the upper lever that turns on A/C, heat, vent, defrost.
    Any ideas??
     
  2. HarryH3

    HarryH3 1 ton status Author

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    I think there are some little sliding clips that adjust the cable. Look at the end farthest from the control. You should find it there.

    I had a '77 K5 that always blew air out of the heater vent, no matter where the controls were set. I removed the main plenum under the dash, prepared for a real hassle. Instead I found a BIC lighter that had apparently fallen through the defroster duct. It was keeping the air door from moving. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    http://ThunderTruck.ColoradoK5.com
     
  3. Boss

    Boss 1/2 ton status Author

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    Hey Smack, I had that same problem on my 75' K5, the problem that the you can't move that lever all the way to right or left. Well, what I did, was I sprayed some Silicon lubricant in there, through the very small gap, and let it sit for a bit, and then pushed the lever to the other side. I then sprayed some more in, and move the lever from left to right a few times and magic, it now moves all the way. Not sure if this method will work for you but, it definately worked for me. Might as well try the simple stuff first. Good luck.
    Boss
     
  4. smack

    smack 1/2 ton status

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    Ahhh those good 'ole biks. Never now where they'll turn up.
    I know that the rod has provisions for adjustments so I'll try that for the hot/cold lever but why doesn't air blow out the dash???
     
  5. 90K5

    90K5 1/2 ton status

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    Are all of the ducts hooked up? In my dash one of them used to come off all the time but it was the one above the glove box and you could open it up and put your hand in to connect it again. Also maybe a switch is not working. Sometimes they get messed up. You could take them out and see if there is lint or other junk like a lighter in there that keepsa the conection from working. If you have to get a new switch they are only like $10 at AutoZone.
     
  6. HarryH3

    HarryH3 1 ton status Author

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    Where is the air coming out? It has to be going somewhere... The door that controls where the air comes out is just above the right side of the tranny hump. 4 screws hold the curved fiber plenum in place. Take that out and look to see if the door moves when you cycle the controls. (This is where I found the BIC lighter in my '77).

    The door is moved by a vacuum motor that's controlled via air-logic built into the controls. The position of the control determines what moves and how much.



    <font color=black>HarryH3 - '75 K5</font color=black>
    http://ThunderTruck.ColoradoK5.com
     
  7. det45

    det45 1/2 ton status

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    My K5 heater lever does not slide all of the way to the cool setting. I followed the cable all the way to it's connection behind the glove box. Didn't see any adjustment? Please help me too.......
     
  8. Espen88k5

    Espen88k5 1/2 ton status

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    I'v heard those litle metal-handles on beer and soda cans, that your friends flipp at each other, trying to take an eye out, often is found to be the problem..
    They get stuck and wont alow the airvents to open or close propperly.

    <font color=blue>Espen88k5 at: </font color=blue>http://espen.coloradok5.com
     
  9. smack

    smack 1/2 ton status

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    Air mostly comes out of the bottom, although some does come out of defrost when set to that. Taking that panel off confirms that that revolving plenum-thing that directs air either up or down is turning but I'm wondering if when I put it back toghether I put it in 180 degrees out because as far as I can tell there's only two ways to put it in. I just don't want to rip the whole assembly out and apart again. Anyone have a picture??? Or maybe one laying around out of a truck in the back of a garage???
     
  10. Jeff 86K5

    Jeff 86K5 Registered Member

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    Talking about the Bic lighters in the defroster....

    A buddy of mine was coming home from his watch on the fire department after a rough night of firefighting. It was about 20 degrees and the water was freezing as they sprayed it on.

    Any way he was driving on the 4 lane about 70 with the defroster going full tilt in his Chevy pickup when the explosion happened. So of course he slid to a stop, jumped out and did a 2 second 100 yd dash thinking the whole truck was going to go. And not know what had happened.

    After a while, he got back in it and came on home (with ringing ears) and little pieces of a green lighter were coming out the vents.

    Though not recommended this also is a good way to remove dust from your vent ducts.

    Jeff 86K5
     

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