It seems that I am one of these people too. I had the radio issue for a couple of years...any source, but only when moving. I could play it under half volume, but that really isn't very effective while moving. In the driveway, it always sounded great. I took it in for warranty repair, and it took 3 trips to finally get them to send it in. First time, they "couldn't reproduce" the issue...even though it was NEVER intermittent. I don't think they listened. They probably didn't even drive it. Second time, they "fixed" it, but a mile down the highway, I turned around and took it back. No improvement. Third time (this dealer is like 40 miles away from me) they sent it off to Radio Sound. Something worked, because it was fixed for my trip out west. This spring however, same issue again. Now, my warranty has expired, and Kutter H-D says sorry...Radio Sound supposedly told them 6-month warranty on repairs, so sorry. Apparently I'm screwed all the way around.
Any tips for me? Things I can check myself? I just sent an email to Radio Sound to see if they indeed won't stand behind their repair. I'm totally pissed about this mess. If they had figured it out the first couple of times...it maybe would have failed again in the warranty period, instead of just after.