My dad and I both have 1999 f-150s and thanks to this site i should be able to fix both of our intermittent odometers. however on his pickup the led lights for his radio and time display go dim too. If you push on it it will light back up and be bright again for a little while but it soon goes dim again. Also on my pickup if you have just the left front speaker on all you hear is a buzzing noise. I have swithced the speakers side for side but it didn't follow the speaker so i know that the problem is somewhere else. If you open the door up about 6 inches the radio comes in clear as a bell. Anybody have any ideas as to where to begin looking for either of these problems?

 

You seemed to have given yourself the directions to look in.
Radio lights; take out the radio and see if it is internally sensitive to shock/ movement by it'self.
Opening the door suggest the speaker wiring thru the door jamb has a problem.