1993 C1500 Odometer issues - need to test odometer motor

Long story short, the odometer has stopped working at 208,790 miles (sometimes it sort of works) on my 1993 GMC C1500. I noticed about a month ago the miles weren't really changing. Since then focusing in the operation of the odometer I would say it either flat out doesn't work or when it does work it's about half the speed required to have the correct mileage. The speedometer works fine and I've checked it's accuracy with both GPS and my wife pacing me in her car.

I disassembled the instrument cluster and confirmed that the individual numbers of the odometer are free moving, with no chipped gears or foreign debris in the gears. Is there a way to test the motor to see if it's operating correctly? Is there a source for rebuilt or new odometer motors?

Thanks for your help.

Okay so does anyone even know the volt input range for the odometer motor?

They usually do not fail. Just pull another from a junkyard cluster.

Richard

That's why I was asking if I could test it... In my area finding a 88-98 GM truck in a junkyard with a single usable part is like finding a needle in a haystack. I want to confirm the motor is the issue before I search for it, in my view there are three factors: the elec. signal, mechanical issues like a broken gear and finally the motor. I've confirmed the gears are okay, now I want to check for the elec. signal. I'm fairly certain that is fine too since the speedometer works but still I want to cross it off my list.

Thanks