I'm putting a newer heater into my '53. The heater donor was, I believe, a '56 and the heater is a fresh air recirculator type. The switch was with the heater and has three connections and I could ohm out the common and the two different high and low connections. The motor lead ends were alreay disconnected and damaged, so I don't know what is what, but two of the ends had bullet connectors on them and the third I couldn't tell what had been on there.

I can ohm out one circuit between two of the leads, but get nothing when trying to find a second circuit in the blower motor. Everything else shows open. I assume that one wire from the motor goes to ground on the firewall since there was only a two wire harness going from the switch to the motor.

Have I got a bad winding? How is this suppose to work? The manual says that the switch lowers the speed by introducing resistance at the switch, but my ohmmeter doesn't back this up, both connections are essentially 0.4 ohms, which is what the ohmmeter reads when shorting the tips.

?????

-Scott
Deeply into wiring mode...

 

I thought one wire is energized for low speed and both for high.

 

Try this, I did it on mine. One wire (black) should be ground. Place the other wire on a 12v hot and you should see the motor spin. Try the other wire and see if it spins faster or slower. That'll tell you which wire is low and high. Then just wire it to the switch. One hot to the switch and one wire to low speed and the other to high. Then ground the wire on the frame or whereever you get ground. The switch should be a two speed, one click and its on low. two clicks, high. Pretty straight forward.