Speakers don't work when it rains, amp or Ant. wire?
 

I have a 99 Silverado and when it rains or when I take it through the car wash the speakers stop working. When they stop working and I'm in the truck to hear them stop working they fizzle or crackle out kinda like bad reception on a radio. In other words it does't just shut off. The display on the radio works fine, it shows the radio station correctly, it switches to CD and Tape correctly and it shuffles through tracks as well. When the sound does comeback and I'm in the truck it usually fades in just like they fizzled or crackled out. When I start up the truck and everything has already dried the sound is blasting.

Obviously the water is causing a short but where it is I do not know. The rubber boots in the door jams are still intact and are protecting the wires fine. I don't know where the amp is so it's possible it could be the amp but that would mean I have a leak somewhere. The other possibility is the ANT wire or the ANT itself.

Has anyone ever had this happen or have an idea of what it could be?

Thanks,
Mike