Have a friend with a 123 T/D sedan which lost all his freon due to a leaking high pressure switch. No problem, replace the switch and recharge system. All works fine for a few weeks until no cold air again.
This time the compressor is running but the blower does not. If you jiggle the key back a little in the ignition, it works. No problem, faulty switch. Replace it. But why if you remove the A/C fuse do both the compressor and blower quit, while the ignition switch only affects the blower? Is this some strange Teutonic procedure or is the compressor wired in through the back door?
Please give me some insight into this. Thanx.

Tobias MB
300SE, 300CE, C280Sport, 190/5.0

HI, yes MB does do strange things with blower motors. The Ignition switch on most older cars did have a circuit just for blower motor & nothing else (15X). Since blowers with A/C/C use upto 30A, they deemed that necessary. On later cars like your W140 S-Class there isn't even a fuse for blower & it's not even switch off w/key! In other words circuit 30 directly from Battery! So that rest function will operate w/o key.