Another Heater motor thread

Ok, Went to autozone and bought a new heater blower motor for my five. It turned out it looks just like the one that was in that Chevy Blazer motor write up. The serial # on the original crossed to that one.

That write up talks about putting in resistors to accomodate the 2 speed switch, but is there a way to use a different switch and go ahead and update the whole system? I'm also interested because my switch is pretty corroded.

 

they make or use to make a variable switch. it consisted of a resistor made on the back side of the switch. it was a turn style switch. kinda like a dimmer switch in your house

 

I don't think there's much you can do to "update" the switch. These are DC motors, and all you can do is run it full speed, connected directly to 12V, or reduce the speed by reducing the voltage. A resistor in series with the motor drops the voltage to the motor, nothing more.

Plus the resistor gets warm, so the factory scheme of putting it in the air stream in the heater housing seems like a good idea.

You could make a DC-to-DC converter to boost the voltage to the motor, but that would be running the motor above its design voltage/speed. This will shorten the motor's life to some degree.

 

I have an extra sw and blower motor for my 66 and tomorrow I will check they system out as I am re-installing that same system in my Tux tomorrow. The sw has three terms, ine which is power in and the other two terms go directly to the two wires on the motor. There is no resistor used for this system although it is a 2 speed. I may have to open one motor to see how it is wired since it is possible one set of windings is used for one speed and power applied to both wires simultaneously for the other speed. Will have to meter out the sw as well to see what it is capable of. Tomorrow is the day.. Walt.

 

As stated above. The switch in low position, powers the single slow (yellow) wire. When switching to high, both yellow and red wires to motor are powered on. Again there is no resistors used with the factory motor and switch. Walt.