I've got two hard vacuum lines coming from the passenger side wiring harness. One goes to the Heater Valve... the other I have no idea where it goes because it's broke off and doesn't have the other end anywhere.

The only open vacuum port I've found is one on a "T" that gets plenum vacuum on the same line that goes to the cruise control.

Could this be why I don't get any heat from my vents? (The door opens)

Help?

Thanks
-Paul

 

is it a black plastic real tiny vacuum line? i only have one and have no idea what to plug it into its so small... im pretty sure its to open and close the heat vents but where the hell do i put it?

 

it is for the heat/aq/c vents, just hook it to any manifold vac source

 

Cars not originally equipped with a heater valve, would only have 1 I assume. Since my '85 Z only had one... and I guess it goes to manifold vacuum!

If you dont have it hooked up you don't get heat, and in my case where that line connected to, was the line for my Cruise Control... so neither worked since it was a giant vacuum leak.

 

One line goes from manifold vacume to the heater control unit in your dash. The other line goes from the heater control unit in the dash to the heater control valve on the heater hose in the engine bay.

 

The one that's not for the heater valve, is the vacuum "supply" to the control head. It gets its vacuum from the vacuum accumulator. In some of these cars, that's a sort of half-cylindrical thing up near the wiper motor; in others it's a black ball about 4" in diameter. Either type has 2 hose fittings; one hooks up to the manifold, the other is where your mystery line goes.

 

excellent. i had a black oval box by the wiper motor. its in the gurage someplace but the line is so thin it doesnt look like its going to connect to it. could i just get one from like an s10 or another GM car if mine doesnt fit? or is there some way to adapt the thin line?

 

Bingo.

There's supposed to be a little rubber connector fitting on the end of the line.

Go to Auto Zone or Advance or CSK, look around on all the spinning displays near the fuel filters, you'll find what you're missing.