Ok so I just replaced the heater core in my 81 El.
I noticed this thing with two metal coils on it.

What is is and how can I tell if it is working?

I thought it might have something to do with my defroster.
I removed it from the heater box, turned the key on, and turned the defroster on.The wires were still hooked to it of course.
I left it for several minutes, I thought it would get red hot or something.
It didn't.

It will not get red hot. It's part of the blower speed control circuit. Each coil has a resistance that creates a voltage drop across it. It is mainly a voltage dropping device which limits the voltage to the blower motor for the different fan switch settings.

Thanks

My speed controll works so I don't think it's broke ay :lol:

buy the manual. it explains this and a lot more.

buy the manual. it explains this and a lot more.

Thank you Mr. Joe Helpfull. :roll: