Tail lights working on and off...

[Badboy2777]

I must have something lose. I get the tail lights to work and I can bang on them all day long and they wont go out but when I take the car out and start driving it they start going out. The right rear side goes out most of the time and sometimes the left rear but that is rare. IT is the brake lights that usually go out. Anyone else have this problem? Some type of factory default?

Thanks