2kVeilsideGTS, since they are McCuloch... did you just install them, or did you modify them to remove the "train tracks" (two dark lines on the ground that exude from the base of the car outward)
The "train track" is caused by the shadows of the return wires. The return wires MUST be facing down. I don't know why McCulloch have their wires facing up. However, to turn the bulbs upside down, you would need to modify the bulb base. It takes seconds to do with a dremel.