3rd brake light(CHMSL), dome light and radio speakers not working

[MrTunaCat]

I bought an old 2003 dodge ram 2500 5.9l Cummins Diesel and I can't get the 3rd brake light to work. I checked the fuse and replaced it with the right one. My cargo lights work but no dome light either

My truck was an old state truck and had a top siren type light hooked up but I removed it.

Any ideas what I can do?

 

[Lyle Longboat]

Hey check your wiring harness on the back doors to the cab. There is a rubber cover on them. These wires are often broken inside the cover and need to be soldered back together and covered or the wiring harness need to be replaced. Very common problem and you will lose speaker, dome lights and 3rd brake lights.