I actually have some trouble with the heater unit .

The air produced is just a very very very tepid.

I have a stationary heater (webasto) installed . It power on and seam to produce heat. It's "hot".

I inspected the 2 ducts that enter in the binnacle and feed the heater radiator: they are hot , and the temparature seams to be the same in and out...

So :

1 - With Webasto ON , car engine OFF : Very very tepid air
2 - With Webasto OFF , car engine ON , (after 15/20 minutes) : same very tepid air.

I downloaded the heater diagram and i see some "air mixture lever" . Perhaps are they blocked ?

Or a temperature sensor that is KO ?

Thanks for your response