Weird short?

[Green_Elite_Cab]

Yeah, this is a tough one. I got the power truck on the Arrow III fixed "good enough", so that it runs, although there is still a slight humming that concerns me. I took it apart, and all the wiring was straight forward, it did not seem like there is somewhere for there to be a short. the truck is literally a motor with wheels attached to it in a nice case, and the contacts were specifically made so that DCC would be an easy install. When it runs, it runs as good as any athearn blue box kit, but when its sitting there it still makes noises.

I still have not been able to solve this problem on my friend's M1A. the wiring on that thing is way to intimidating, and i only got it to work for a short time, so there is probably something loose in there that i can't find. I just don't want to tear that thing down into its individual pieces.