stilllearning6

1989 Dynasty 3.0 liter : lost the vacuum signal to shut off the heater hose supply of hot water to cabin. I believe that the signal comes from the Heater A/C temperature Control Switch ( lever arm ) on the dash.

I want to trace the vacuum signal to its origin ( I suppose at intake manifold).
Can anyone pinpoint where on the intake manifold this vacuum hose is connected?
Perhaps mine was disconnected at the intake manifold. Hope so.

pro-tech

Yes it is manifold vacuum..Bill

stilllearning6

I believe that the vacuum source for the interior temperature control unit originates at the vacuum brake booster as a thin black vacuum tube running from the vacuum brake booster through firewall to the interior dash temperature control unit.
If anyone knows differently , kindly advise.