Testing blower motors from an old bus

Asked by Aug 16, 2016 at 05:49 PM

Question type: Maintenance & Repair

I have several old blower motors from a school bus and cannot get them to
work.  As far as I know, they worked when installed in the bus, however now I
am simply wanting to test them in a workshop.  I am hooking them up to a 12V
battery using lead wires.  There are two wires coming out of the motors.  Any
insights greatly appreciated.

4 Answers


Back in the day you could change rotation by reversing polarity, that way it fit more than just one style of system. so it depends on what type of blower or fan is on it as to which direction the motor is suppose to run. Make sure you have the motors secure before hooking up power, some of those old ones had some torque.

thanks for the reply! i've tried reversing polarity on two of them with no detectable result. (in all cases, there is just nothing happening when i connect the wires).


Then try grounding the case and try one wire at a time.

tried grounding case and one wire at a time. I'm now going to see if I can find a wiring schematic for these blowers and replicate everything, resistors etc Any ideas where I might find such information online? This is a 1970 bluebird school bus with GMC engine - C/40 gasoline.

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