Hi all,

I want to fix an issue on my 1979 E12 528i: whichever way I turn the heater control (hot/cold), the heater stays on and heats up the interior of the car. Nice in winter, but quite annyong in summer!
The switch is connected to a pole which in turn operates a valve of some sort. This mechanical connection works as checked from looking under the console/dashboard.

What else could be the problem with the heater staying on?

Thanks, Marius