I've done a search but am not getting anything precisely for 124s.

My fan fluctuates up & down. I plan to replace the brushes in the blower motor but am unsure how to test the blower regulator. I'm aware of it's location and wiring but just don't know test procedures. Would someone please be kind enough to give me a simple explanation of how to test the blower regulator. Also, I'm assuming it's only operational when the climate control is set to auto vs. low or high?

BTW, this site is awesome! Guys like GSXR, Hatterasguy, & Bilble are radical & have kept me from asking thousands of other questions.

Robert