My tail lights do not stay lit (running lights), but the brake lights work fine! I have checked the wires and there seem to be ok (all attached and not lose). What should I do next. All fuses are ok as well!

Cellus

 

Replace the bulb. Someone correct me if I'm wrong but if they are like car taillights they have a dual filament, which explains why your brake lights work but your parking lights don't.

 

true true.