My mercedes tech is diagnosing the problem now. We took out the hampster cage (blower motor under rain you tray) and tested it independently -- it works.
Next we got the refurbed control panel and installed it...nothing, no power to the blower. Checked the fuses and relays and all seem to be working.
Guess the next step is multimeter the harness for broken wires? I wish it was an easy fix, so cold driving around with no heater.
If you blew the 30 amp fuse the fan is drawing too much current & is on its way out I'll bet....
Good thinking but not necessarily so. German fuses are a lot like beer cans. If you bend them back and forth enough times they will snap. When current flows through a fuse, it acts like a tiny resistor. The heat produced during current flow causes the fuse metal to flex. As the metal cools it relaxes. This constant flexing back and forth eventually causes the metal in the fuse to snap. In most cases there is nothing wrong with the circuit. All you need to do is replace the fuse with a fresh one, and the flexing begins again.