Do I need to replace my blower motor if my technician says the regulator is bad.

I think the brushes in the blower motor are short causing the motor to work when they contact the armature and stop when the contact is lost. The regulator is probably good, the next time it stops tap on the motor with a small hammer or the handle of a large screwdriver if the motor takes off and runs it's the motor not the regulator, I hope this helps you.