Arvin under dash heater

So me and my boys decided to go out before the rain to tinkeron the 49. We were clearing out all the old wiring and rotted ducks. I unhooked the heater hoses and noted it still has antifreeze in it and no leaks in the car; of course I didn't pressure test it either. I removed the heater from under the dash and was able to drain the rest out. It has a single wire to it. The fan turns, switch turns and clicks and has a good bulb in the knob. 1st question is the single wire positive or negative and would it be worth putting back in since it is a big unit and sticks down low?

Flaps work


And the fan turns easy


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I hope i just didn't make a double post.

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You did.

 

Positive, most likely. Ground is the car was the car you took it off of negative ground? And yes, it will work fine on 12 volts.

 

Bet it works good if cleaned up. Probably needs some lubrication by now. Use something dedicated for electric motors. 3 in 1 makes an oil for this, comes in a blue can.

It would have to be positive ground, not sure it makes any difference on a fan? It doesn't on a starter for example.