Testing blower regulator w124

[fb111]

I have removed the fan and regulator and determined by my lack of voltage on the three pins behind the brake booster that I need an ignition switch. I'd like to put the fan and regulator back together with the wiper but do not know how to bench test the fan regulator. I tried putting twelve volts to the red wire and ground to the black wire and the fan does not work. Is this a way of testing the regulator? I also tried 12 volts to the yellow wire and ground black and the fan didn't work. The fan does work if I apply voltage to it directly. Any help would be greatly appreciated!