re: 83 300SD

I have two blower motors apart and can run them on a 25 Amp power supply I have on my bench.

They draw about 15 to 20 amps according to my fairly accurate ammeter.

If you can find a 1-2 ohm 25 watt resistor to put in series with the blower, you can temporarily drop the amps draw to around 5 to 10 amps...

I believe that the blower regulator/resistor does that function in the car itself, but I am no technician regarding this setup.

A charged car battery will work in place if a power supply for testing out the blower.