Vacuum issue with engine stop and climate control

[Phil]

I just finished resolving an issue of an electric short in the dash board and put everything back together but now have a problem that every time I press any button on the climate control it shuts off the engine. Is there a check valve or something that seperates these two systems that could be bad?

The car had been sitting for about 3 months while I tried to get time to fix the short and now this.

Also the windshield defrost will not close so I have hot air all the time. Can any one tell me where the vacuum pod for this function is?

[uberwasser]

Sounds like you mixed up a line. Vacuum is normally kept away from the shutoff by the vacuum switch in the ignition until the driver turns the key out of the RUN position.

What likely happened is that you accidentally connected the line that feeds vacuum to the shutoff from the ignition switch to your climate control. Your climate control, when turned on, is designed to feed vacuum to the various pods behind the dash. It's now also feeding vacuum to the shutoff.

On the W123 chassis the shutoff vacuum lines are brown. Not sure on your car...

[Phil]

Originally Posted by uberwasser

Sounds like you mixed up a line. Vacuum is normally kept away from the shutoff by the vacuum switch in the ignition until the driver turns the key out of the RUN position.
...

The thing is I didn't disconnect and reconnect any of the vacuum lines. I did replace the ignition switch and I am wondering if I could have rotated the switch partway before putting it back on the key assembly.

[jay_bob]

Or you swapped the 2 lines behind the switch. The switch is a 3 way valve - the third point is a vent hole - and the 2 lines are not interchangeable.