How to test a DC PWM motor speed control

I was given a DC 12V-40V, 13khz Pulse Width Modulation (PWM) Speed Control for use with a DC motor. It has no documentation. There are only 4 terminals with 2 labeled "In" and 2 labeled "Out". When I connect a 12V DC supply to the "In" terminals and a 12V DC motor to the "out" terminals, it does not run. Regardless of polarity of the 12V supply and position of the speed control knob (see attached pic). I also see no reading at the "out" terminals on my multimeter in AC or DC voltage modes.

Is there an easy way I can test this device to determine if it is working or dead? Of have I already done that?

Thanks for the help, I have not used one of these devices before.

View attachment 64940

Maybe that's why you were given it? Probably the active IC got clobbered when the polarity was reversed accidently.

Try a 12 V light bulb as a load.

Take a look here and look at the datasheet: https://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_120539_-1

If you can identify the IC p/n in the product, most of the info that you need could be found by Goggling "Datasheet p/n"