The heater ducts on a 1993 Buick Regal are not working ~ they are stuck on defrost. I suspect a vacuum leak is causing the issue ~ where is the vacuum hose located so I can verify this?

  • Welcome to Motor Vehicle Maintenance & Repair! Jul 4, 2018 at 14:40
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    usually runs along the passenger side of the engine bay.
    – Ben
    Jul 4, 2018 at 14:53

1 Answer 1


If i remember right there is a vacuum solenoid box under the dash on the passenger side, they are notorious for the hoses and connectors inside the box to disintegrate, you can open the box and re plumb it. You can follow the vacuum lines as all the actuator lines go into it. Be sure to take a picture of the inside before you start repairs.

First check the vacuum supply line under the hood is intact, it will go from the intake manifold thru the firewall. Small diameter plastic line, usually black.

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  • If it is the solenoid box and you dont want to repair it, rockauto has one for $56.70. AC Delco PN1572182....rockauto.com/en/catalog/…
    – Moab
    Jul 4, 2018 at 15:09
  • Where does the supply line go through the firewall?
    – RET
    Jul 4, 2018 at 15:23
  • Not sure, somewhere on the passenger side near the top. It will be the only vacuum line going through the firewall. If it is black it might look like a wire since it is so small diameter. (1/8")
    – Moab
    Jul 4, 2018 at 15:25

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