Logically there are only two things that would cause the tail light to burn out.
A short is NOT one of them. If the hot lead shorts, NO lights...if the ground side shorts light just flickers.
If the bulb is fragile...as the other dealer says then the hot filament could bounce around and break easier.
But more likely the culprit is a surge in voltage which will kill a light bulb quicker than you can say Johnny Walker.
The later might be hard to find without swapping parts with another machine.
Since not many guys complain about tail light burn out, I suspect they you might have bigger fish to fry as it can kill the headlight, dash lights, and maybe even the hand warmers, eventually too.
I purchased a cheap digital compass that plugs into a cigarette lighter. Not only does it keep compass direction but it tells the inside and outside temp (same on a sled...obviously) but it also has a constant read out of the voltage.
Amazon sells them for about $35. You can tell if your voltage is spiking and killing your bulbs. It is surprisingly accurate. And when your done with your trouble shooting, you have a lighted digital compass for your sled.
