1986 190D here.

The side vents on my 190D constantly blow hot air.
If I close them off and turn on my a/c it blows ice cold out the center vents but I have to close the side vents or it will blow hot air.

It blows hot when the thermostat dial is at the coldest setting and the hottest setting...doesn't matter where it is.

I did have the gauge cluster out yesterday. Could I have disconnected a vacuum line?

Thanks in advance!