I also posted on mercedes shop
The blower motor comes on for 1.5 seconds after each engine start if the engine exceeds 1200 rpm. It comes on if the temperature in the box is over 60C, and off at less than 55C for 6/8 cyl (5 degrees less on the v12). The air is drwn from under the dash and returned to the blower housing. it is controlled by module N16/1 in the box (the one with the fuses) it must get its power in there. I found the info in my 92 140 intro to service manual, and also believe it was deleted some years later. I cant prvide any more info than that.
The blower motor comes on for 1.5 seconds after each engine start if the engine exceeds 1200 rpm. It comes on if the temperature in the box is over 60C, and off at less than 55C for 6/8 cyl (5 degrees less on the v12). The air is drwn from under the dash and returned to the blower housing. it is controlled by module N16/1 in the box (the one with the fuses) it must get its power in there. I found the info in my 92 140 intro to service manual, and also believe it was deleted some years later. I cant prvide any more info than that.