Chris:

Well, this is gonna sound weird, but here goes. I had similar symptoms with my radio, which has an amp wired into it for the back speakers. The amp was was stuffed up under the dash behind heater fan and such. Sometimes when I braked, it would go crazy with static. The other day it was the rear wiper that set it off. I also thought it was short or crossed wires or something. But what I found out was that the main connector leading into the amp was being bent, and that when inertia from braking caused pressure on it and it bent more, it would cause static. If I bent it myself in a similar fashion, it do exactly what was happening before.

I have no idea why using other electrical things such as the rear wiper would cause it to occur as well, but it did. So you may want to check the connection to your amp (if you have one) or the main connection to the radio. Perhaps it's loose, or being bent as was mine.

I know this sounds too good to be true, but in my case that's what was causing the problem.