heater decides not to switch off

[sean sherry]

Ah the mysteries of Mercedes vacuum system !

Drivers side heat slide control does not apply vacuum to the heat valve. Passenger side works ok, switching off the heat.
Heater switched on yesterday , but then would not switch off. All the vacuum connectors behind the panel are good. I can't see where or how the slides operates the vacuum to the heat valve. Is it buried further down into the Dash ?
Thanks Sean

 

[Helmet]

Is the lever going all the way down Sean ?

 

[sean sherry]

Thanks Helmet..... either I'm confused or the car is... or both of us !
The switch off controls alternates between Driver and Passenger depending on where its neighbour is set. Could be how it works, though I have never noticed this before. I'm not going any deeper, I can live with this now that I know.
Sean