There’s a blower motor connector above the brake booster. IIRC it had a big red wire, a big black or brown wire and a yellow wire. The yellow wire carries a 0-7V signal to the blower controller. The red wire basically hard wires +12V to the blower motor. The black or brown wire goes through the controller and based on the yellow wire signal is PWM’d to +12V (off) to 0V (max). In short, check voltage at the yellow wire to see if the PBU is telling the fan to blow. Many of these cars have a dedicated 30-amp strip fuse for the blower motor outside the engine compartment fuse box.

Sixto
98 E320s sedan and wagon