My 1955 Super 88 has a three position heater fan switch; high, low, and off. The fan motor has only two wires, one is a ground, the other is power. The fan runs on low speed in both the low and high positions. Off works. I read somewhere that a resistor or some other electric gadget is responsible for changing the speeds. Where is that gadget? In the switch? In the heater box on the engine side of the firewall? Somewhere else? It’s starting to get cold here in Kansas and I’d like a little more control of the heater. The heater does put out warm air and the fan motor is new. Ideas? Solutions?

 

The blower motor speed control resistor is mounted in the heater box and looks like this. This thread has a series of good photos.

 

That’s just what I needed to see. As soon as I get a warmer day, and finish the wife’s honey do’s, I’ll crawl under there and see what I can find. The pictures should help. Thank you.

 

Note that there are actually three unique motor speeds, LOW, HIGH, and DEFROST. Both heater speeds go through the resistor. The defrost switch bypasses the resistor and runs full power to the motor. If the defroster switch is stuck on, you will only get full speed no matter what setting the switch is on. (yeah, this is a 1956 wiring diagram - the 1955 heater works the same way)

 

Thank you. I’ll check the defroster.

 

Also, check the connections. As I mentioned in the thread that Joe referenced above. I got my '56 to work by just cleaning the contacts.