Tail lights stuck on until I turn the interior lights on

look for any cobb job wiring under the dash from a previous owner , or get a multi tester and trace the wires back from the rear lens , old worn sockets can do funny things , everything needs a ground too

I have been replacing all grounds. I am still having issues. I have brand new tail lights that are maybe 2 months old. I haven't had an issue with them before.

you can't see electricity you need a multi tester to know what's getting power and what's not

I have a multimeter. I am trying to figure out where to start. I have been told that its a ground. I have been chasing down grounds and replacing them. I thought it might have been the headlight switch because there is that dome override switch. I can turn the dome lights on and it turns the taillights off. Once I turn the dome lights off the taillights come back on. I decided to unplug the headlight switch to try to eliminate that and it still does the same thing.

, auto electric is usually a learning experience for me also , headlights are hot at all times (hat) for any vehicles along with horn ,brake lights , cigarette lighter , etc. , draw up your own diagrams to help , haynes manuals have wiring diagrams but any other chevy truck would be similar