I have an 03 Ultra that loses ALL Power, radio, lights - EVERYTHING. I think the main breaker is getting thrown. It resets after a couple of minutes and I can restart it. It is not doing it consistently, so it is hard to pin point what is causing it. I have taken it to the mechanic three times and am still having the problem.

 

have you tried replacing the main breaker? although not very common, the contacts encapsulated within the breaker can go bad causing this type of behavior...

 

I believe there was a recall for the main breaker on this year. I would replace it so it dont quit in bfe.