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Main Vacuum Line from Engine Compartment to HVAC Control Switch

Discussion in 'Interior' started by Dodge_In_AZ, Jan 25, 2020.

  1. Dodge_In_AZ

    Dodge_In_AZ Junior Member

    Likes Received:
    Jan 25, 2020
    Ram Year:
    2001 Dodge Ram, 5.2L, 4x4

    Hi all. This is my first time posting.

    My truck vents stay on defrost vents only. I have researched and found that when this happens, it is most certainly a vacuum line problem. While tracing the vacuum lines for the HVAC system, I found that the main vacuum line from the engine intake connection to the HVAC was missing (most likely mice). My question is, how hard is it to get to the back of the dash and install a new vacuum line run like that of original spec?

    I have not been able to find a drawing of which colored vacuum lines go where in the interior, so through my own hand over hand tracking I believe the black tube that connects to the HVAC vent switch is the main line connection from the engine. Is that correct?

    Would it be better to bypass the original spec, and run a vacuum line from the engine intake connection directly to the HVAC vent switch?

    Any help would be greatly appreciated. I have heard horror stories of people replacing their dashes after they have cracked. My impression was that it is a nightmare to get the dash out.
  2. Mop

    Mop Member

    Likes Received:
    Aug 5, 2017
    Ram Year:
    No need to take the dash out. Buy 3mm rubber tubing. About 5-7 feet is fine.
    Take the black border surrounding your gauges out. It has tabs, so it pulls out. Be gentle, don't muscle it, it will pop out eventually. You might have to adjust the tilt steering. Then unscrew the climate control and radio. It will make it easier to maneuver the tubing.
    Attach the rubber tubing to the broken end under the hood. Run the other end through the firewall nearby. It will appear under the dash, on the passenger side.
    This is the tight part. I used a coat hangar behind the hole where the radio does. Grab the tubing, pull through. Then, snake it behind the climate control area.
    Clip the BLACK line behind the climate control, leaving 2-3" of slack to attach the tubing. Turn the key, try it out. It should work. Then, put the radio, controls, and dash moulding back.

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