Alldata sells single model access and they use factory wiring diagrams.
The blower and regulator are not inside the car. They are accessible through the engine compartment. There is a three wire connector that is on the firewall, easily accessible, next to the booster. Inside are the power wire and the control wire to the blower. The yellow control wire should have 1-6v on it in response to changing blower command at the push button assy.
If the command is there and power is there then you will have to expose the blower to tell if its the blower or the regulator that fails the circuit. The regulator makes the ground side of the blower circuit with the blower always having power on it.
Bosch Master, ASE Master, L1
33 years MB technician