How many ohms for blower motor resistor?

[davepl]

My original looks good (in the sense that neither side is an open circuit or blown), but I can't find a spec for what it should measure at (1970 AC truck).

I don't want to put in a Chinese replacement if my 40 year old GM unit is still good, but I'm a long way from powering it up and testing it empirically.

Anyhow, from the base to one port I get 0.6 ohms
From the base to the other I get 1.5 ohms

Those are really low numbers, I actually get different numbers on different meters and they swing around a bit. Maybe low battery in a meter?

Anyway, if someone knows that numbers should be, please let (me) us know.

[68c10airstream]

Hi Davepl, i just received my gm replacement from my local gm dealer for a stock 67-72 ac resistor and i believe it listed for under $20.00. I took the gm part # ( i believe 7 digits) and called the gm dealer and was suprised it was still avaliable and how reasonable it was. The part# was stamped into it. If you can't find out i can dig mine out. On the resistor, the purple wire that leaves the resistor to go to the blower motor is the common terminal for one of your dvom leads. Then touch the other lead to each individual remaining terminal, one at a time and that would be each step in the blower motor speeds. Shot from the hip, i think your readings are close. If the resistor is rusty at all replace it, as this will cause additional resistance and heat and be hard on the plug in at the resistor block. It also wouldn't be to fun to get at once it is all installed back into the truck. Good luck, Brian Fuller

[davepl]

Thanks. I completely cleaned it to like-new and made sure the coils were spread so any current couldn't just run linearly down it.