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Hot Rods My heater works but the dash vents and defroster doesnt on the olds wagon

Discussion in 'The Hokey Ass Message Board' started by Bruce Fischer, Dec 21, 2015.

  1. Everything comes through the lower heater part on the floor. It wont switch over to the dash vents or defroster vents . Is there some kind of vacuum control I should be looking for that's not working?All the cables seem to be working. Any ideas? Thanks and MERRY CHRISTMAS to you all Bruce. 001.JPG
    Last edited: Dec 21, 2015
  2. How about the other end of the cable that attaches to the door in the heater that directs the air flow. I have had them break at that spot or the door itself is messed up.
    lothiandon1940 likes this.
  3. Inked Monkey
    Joined: Apr 19, 2011
    Posts: 1,831

    Inked Monkey

    If it's like mine, the cable that you pull for the defrost can only be opened half way like the temp controller on that circuit. I think it shares a flap. Like wraymen stated, I would check the box end of the cable.
  4. rtp
    Joined: Aug 14, 2007
    Posts: 181


    Bruce is it on the 72 wagon? My cutlass did the same thing years ago .Small vac hose to a vac switch on the heater control was leaking. control lever has a a rotary vac valve (switch) that controls the vents. Small leaks (that you may not hear) wont let the vac cans close the vents. Also the rotary valve (switch) can leak .
    Just trying to remember what I did to repair it . If I think of it I will let you know.
    loudbang likes this.

  5. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,398

    David Gersic
    from DeKalb, IL

    Are the doors cable actuated? Or vacuum? Or electric? You'll probably need to pull the HVAC box out to have a closer look at how it works.
  6. Thanks for the tips guys I will check them all out. Bruce.
  7. gatz
    Joined: Jun 2, 2011
    Posts: 1,579


    Did one (or more) of the flex-hoses fall off?
  8. carguy699
    Joined: Jan 16, 2013
    Posts: 87


    I strongly recommend getting a factory shop manual for your olds(ebay?)!! it makes it SO much easier to figure problems like this without any guess work!!
    merry Christmas!!
    302GMC likes this.
  9. donno
    Joined: Feb 28, 2015
    Posts: 424


    I would bet $ on the rotary/vacuum switch behind the control panel. Changed several over the years on a # of GM products. Never fixed one just r&r'd as they were cheap.
  10. oldsjoe
    Joined: May 2, 2011
    Posts: 2,543


    Hey Bruce check for a vacuum hose disconnected or split on top of the heater box behind the glove box. Also while your looking have someone move the levers for the temp and the floor/defrost/A/C if equipped. have a look at them to be sure they are moving all the way open and closed. Joe
  11. Thanks again for all the tips guys .As soon as my granddaughter{she 6} and I get the sound deadner layed down on the floor I will check it .Thanks.Bruce.
  12. oldsjoe
    Joined: May 2, 2011
    Posts: 2,543


    Heck with the seat out of the way, it will make it much easier to trouble shoot Bruce! Joe
  13. studeynut
    Joined: Mar 13, 2011
    Posts: 290


    Check for blockage of the tubes, I have found mice nests in them before.
  14. Hey Joe maybe you got a point there! lol.Bruce.

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