Safe Jump from Battery to Components?
 

While I'm pretty good doing mechanical work on my 85.5, I admit to being an electrical dummy.

I have several electrical components that don't seem to work (blower motor, window sprayer motor, etc.), and am thinking that there must be a good way to test the components themselves by jumping directly from the battery. For the blower, I've already replaced the large white resistor pack with a known good one, and have also replaced the appropriate relay and fuse. So now I need to do what I probably should have done first...which is to simply test the motor itself. (or the switch, but that is harder to access than the motor).

But I don't want to fry anything...so is there any way I could fabricate an inline adjustable voltage regulator into a dedicated wire that I could then use with my battery to test these components?

Or is there some other, perhaps better, safe means of testing these components?

12v drill battery and some alligator clips.