When Brakes pressed - parking lights, brake lights and dash lights come on.

[gb888]

Here's a strange one. 1996 Galant the dash lights, brake lights, and parking lights all come on when brakes pressed. Replaced a blown 10A brake light fuse on fuse pannel under the hood. The brake lights work, but so do a few others. My son did install a new radio and am wondering if there are any connections located behind the radio that would have caused a floating ground. No blown bulbs, so any help would be appreciated.