My turn signals flash all lights except the cab marker light(the sleeper one) and when you turn the dome light on there soild. Also the dome light doesn't come on. I'm thinking it may be the interruptor switch. Only because the light was flashing( the light inside the switch so you can see it at night). The switch still works. Also found out that the owner before me had hot wire the heated seats fuse to the dome light fuse. Also the lights under bed are super dim. And when you plug something the 12volt outlet in the passenger compartment the turn single lights come on