w124 blower motor regulator test?

[al71al]

hi all,i need ur help on how to test blower motor regulator, i have 230 ce 1990,it has the 2 fan blower motor, the motor is working when i connect it directly to the battery,i checked the voltage on the bar fuse (30A) both sides are ok, i checked the voltage on the 3 pin connecter,its is ok.....now i think it is a faulty regulator...plz any help or ideas ....many thnks