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Vents not working right!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BayouBlazer88, Nov 10, 2002.

  1. BayouBlazer88

    BayouBlazer88 1/2 ton status

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    My 88' K5 is equipped with AC and of course heat and defrost. When I turn on the blower fan, the air blows through the dash vents, the lower floor vents and some out of the defrost vents, which would be fine if the switch was set to Bi-Level, but it's not. In fact, the air comes out of all the holes no matter what the switch is set to whether it be defrost, norm AC, max AC, etc. Does anyone know what the problem is as well as what to do about it? Is there a leak somewhere or a valve not opening correctly? I know absolutely nothing about the HVAC system so any suggestions are greatly appreciated. It's not that big of a deal since I leave my windows down every chance I get, but in the winter I'd like to have as much hot air blowing out the vents as possible. Thanks.

    Matt
     
  2. daleearnhardt01

    daleearnhardt01 1/2 ton status

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    I had the same prob on my 90 Jimmy a few months ago. The A/C man at work looked at it one day and it was just some vaccum lines undone and that wasnt letting the doors and such close and open. Now it works great! Hope this helps /forums/images/graemlins/wink.gif
     
  3. cdh

    cdh Registered Member

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    I did a heater core in my 89 Blazer this weekend and discovered why my vents were not working property. There is a gate in the heater box that controls where the air flows. A plastic clip on the gate was broken and the gate would not fully close.

    It is very easy to fix. On the front of the heater box ( right behind the glove box) you will see a platic cover that sends air the the dash vents. There are only three bolts holding the cover on. Once the cover is off you will be able the see the gate and the plastic clip that connects the gate to the vacuum cable. With the truck running switch the air controls to A/C, defrost, etc and you will see how the gate works and that the plastic clip is broken. You can buy the clip at any Chevy dealer for $1.31.

    Hope this helps.
     
  4. Stoopalini

    Stoopalini 1/2 ton status

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    There's a vaccuum line that tT's off behind the air filter housing, and runs through the firewall on the passenger's side to the controls. I had the same problem you are having, and it turns out the T had split. A 2 min replacement, and it was working again.

    Check for a bad vaccuum line under the hood behind the air filter housing.

    Thomas.
     
  5. HarryH3

    HarryH3 1 ton status Author

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    I had a K5 once that wouldn't blow air out anywhere other than the floor vents. I took that exact same cover off and found a BIC lighter that apparently had fallen down through the defroster vent and lodged itself in the air door, so the door couldn't move. Everything worked great once I took the lighter out. /forums/images/graemlins/cool.gif
     

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