Bad PWM cables?

[Jon Stratis]

The easiest way to tell is with an ohm meter - check for continuity of each wire from one connector to the next, and you'll know if the wire is bad. I have seen bad wires before.- Usually a Nick in a wire that causes a break somewhere. But that's fairly rare and easy to spot if you suspect it of being bad.

Other than that, I would look at how it's being inserted into the speed controller. With some controllers, it's real easy to insert it wrong (either missing the connectors in the victor, or plugging it in backwards)!