"Ted Mittelstaedt" > wrote in message
...
>
> "dprkk" > wrote in message
> ps.com...
> > After living with lukewarm heater performance for too long with my 91
> > GC, I decided to get to the bottom of the problem. I found no vacuum
> > to the heater core control valve. The vacuum line goes into the
> > firewall to the under side of the dash somewhere. What is the
> > suggested way to start troubleshooting and taking things apart under
> > the dash? TIA.
> >
>
> With a 15 year old vehicle you might consider bypass rather than
> repair. For little money you could run a vacuum line from manifold
> to a vacuum valve you just mount under the dash and manually
> operate. Run a line from the valve to the heater core control valve.
>
> Taking the dash apart is a very complex operation. The first step
> is getting the factory service manual and studying the procedures.
>
> Ted
>
>
You DON'T need a vacuum hose from the dash to the control valve!! The
purpose of the vacuum hose is to close the heater control valve when max air
is requested. Apply a vacuum source to the valve will cut off all incoming
hot coolant to the heater core.

Glenn