HVAC door stuck?

Discussion in 'Interior' started by mok4200, May 28, 2016.

  1. mok4200

    mok4200 Junior Member

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    Just purchased a 2001 Dodge Ram SLT 5.2. One thing I noticed is that the HVAC will not blow out of anything other than the defrost vents. No matter what else I turn it to, it is always there. Any quick suggestions on what to check before I rip out the dash?
     
  2. Hemi395

    Hemi395 Senior Member

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    Can you hear any faint hissing anywhere in the dash or I. The engine bay? Might be a vacuum hose that came off or broke...
     
  3. mok4200

    mok4200 Junior Member

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    I do, but I did on my last Ram as well...Where in the bay should I check?
     
  4. Hemi395

    Hemi395 Senior Member

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    I would start on the passenger side of the firewall where the evap and heater core go through. Usually that's where the vacuum lines from the engine bay go inside to the dash. Then crawl up under the dash and see if you can see any vacuum lines. Other than that I'm not sure as I'm not that familiar with second gens...
     
  5. mok4200

    mok4200 Junior Member

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    Good deal, ill check em tonight, it almost sounds as if the blower itself may be falling out of the housing..
     
  6. dudeman2009

    dudeman2009 Senior Member

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    You shouldn't hear any hissing from under the dash, not an air like hissing anyway.

    Both the 5.2 and 5.9 run their accessory vacuum systems off the back of the passenger side of the block. You are going to be looking at a bunch of thin plastic tubes. Depending on whether or not you have 4x4 will determine if there is an unused port on the vacuum splitter, if no 4x4 it should be closed off and not pass any air.

    When my vent control stopped working it was becuase one of the rubber boots for the vacuum line had degraded over time and just came apart.

    A really easy check to see if vacuum is making it to the vent control switch is to change the vent position with the engine off just after running it. If you hear a hissing, then there is vacuum getting to that switch but not the doors. It there is no hissing, i'd go straight to the vacuum hub.

    Hemi395 is right, the vacuum lines enter the cab right behind the engine through the firewall, they are pretty easy to spot.
     
  7. mok4200

    mok4200 Junior Member

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    I appreciate it, ill do that on my lunch (at work currently)
     
  8. mok4200

    mok4200 Junior Member

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    Alright, so, I did the test and I do hear hissing, since it is getting to the switch, any suggestions on the easiest way to trace the lines to the door?
     
  9. dudeman2009

    dudeman2009 Senior Member

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    Not really, you can look under the dash for the actuators, they are cylinders, and try to actuate them by hand after moving the selector switch between settings until no more hissing can be heard. They are spring loaded, but you should be able to move them by hand, I just cant remember which ones are accessible from under the dash.

    If you don't find anything or cant get the doors to move by hand, i'd pull the thin cover thing for the front of the dash. There should be three bolts holding the selector switch in the dash. Pull the switch out and remove the vacuum connector from the back. From there you will need a small piece of tube, i've used small dia. fuel line. From there with the truck running you will be able to tell which line is the vacuum source, jump from the source to other holes on the connector and listen/feel the vents for the doors to change position.

    If the switch is bad, your vents will change state if you can get vacuum to them. If they don't change, you care going to have to follow the lines for leaks.
     

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