Cheak your Capacitor in line with the Resistors. It could be a open Resistor. Is this the one with a couple of solid boards labeled S1-S5 about chest height? you have one with several pot switches on it, one of those is a leveling final speed (I think it is K speed, but dont quote me).Try swapping the board s with the other car, it might ride a little funny, but see if it levels? I don't know what model you have, but that might help. Good luck. I am going to finish my beer now.