I am replacing my heater fan blower and noticed that the replacement I bought from NAPA did not seem to blow as much. After checking rotation and making sure it was clockwise, I used a Tach to measure shaft speed. The new motor spins at 1/2 the rpm as the old one at a full 12 volts. I returned the fan to exchange for another brand that NAPA sells and that too, was 1/2 the RPMs of my old noisy unit.

Does anyone know why there is a difference? Where can I get a motor like my original?

 

Is that a multi-winding motor for speed selection? Meaning 3 terminal connections. I don't think they used resistor banks to control fan speed back in the day? Anyway, it may be the motor was getting power supplied to the wrong low/med connector?

 

1 wire terminal and resistor bank is mounted in the heater box. Looks just like purchased motors but the windings are definitely bigger when you looked in the vent hole.

 

Weird. Never heard of this one. I'm interested in hearing the solution.

- Eric

 

Ah, one wire. Well you're electrically literate and that's in your favor. Surprised the after-market was so far off unless it's a "universal" motor for several applications? Unfortunately, none of them yours.