[DML] Troubleshooting HVAC vaccumn controls

["ryanpwright" <yahoo1@xxxxxxxxxxxxxx>]

List,

I need some assistance with the HVAC controls. I took a hand vaccumn
pump and tested everything today, also traced out all of the vaccumn
connections according to the workshop manual and everything is as it
should be. But I still have a problem:

All A/C positions work just fine - flaps move, air comes out the vents
like it should. However, "vent" comes out the floor, and "heater" and
"defrost" both come out the defrost vent on the dash. Also, there
appeared to be no air exchange at all when I switched between "heater"
and "defrost". Vaccumn gauge didn't move and I didn't hear a thing,
unlike when changing to the rest of the positions.

I rebuilt my mode switch when I bought the car last year, which
enabled the partial mixed-up functionality I explained above. Before
that it was very leaky and nothing worked well. However, I had to glue
the switch back together, as the tabs on the plastic back piece that
hold the whole thing together were broken. I'm positive I put it back
together properly and got a good seal, and the little maze didn't look
damaged to me, but perhaps I missed something.

What do you think? Should I replace the mode switch? Or could there be
another problem?

Looking at the diagram on N:08:15, "A/C Norm" and "Vent" both actuate
the same diaphrams: They release vaccumn on position 3 (recirc/water
valve) and enable vaccumn on position 5 (top mode/face level vent).
Since this works as advertised on "A/C Norm" but not on "Vent", I'm
inclined to believe the diaphrams, tubing, etc, are just fine, and the
problem is indeed in the mode switch. But I'd like some more opinions
before I throw a new mode switch at it.

-Ryan








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