When brakes are applied the back-up lights come on along with the brake lights. What could be the cause of this? Already cost me a ticket...

I would say that the ground is bad on the brake light sockets. When the power goes to the brake light bulbs, it backfeeds through the reverse light filaments to get to ground.

@tenspeed, good one dude! you've got real imagination~

Yes. of course. Bad ground on the light fixture (both of them?), How would a person repair this other than to buy a replacement?

It's not imagination - it's experience from being a master electrician and working in the skilled trades for over forty years. I've seen cars with bad grounds light up turn signal dash indicators. --- You repair it by running a new ground wire. It's a lot easier than trying to find where the old ground came loose.

what comes on when you reverse? some tails have more than one globe for brakes and ofcoarse one for reverse also ,if taken apart and reassembled taillenses pluged globes in wrong holes you will lite the white, now how did an ace bucher like me know that?

got to get the 'lectricity to through to the filament to the plate for ground without condensation ruining the connection. Sounds like solder to me. Do not use and acid flux.

Tail light bulbls are likely mounted in a circuit board. replace the board

2003, and this cat has no money. if it were just a circuit board could not be repaired?