my friend did that with his duramax and im trying to figure out the same thing.. I think he jumpered something in the fuse box.. maybe used a Diode.. cant remember what exactly he said but i was thinking about just wiring them up on a separate switch completely to stay on all the time
Very easy.. i did mine about 8 months ago and they turned out really nice! i have to re paint one because i got into an accident and i plan on putting some LED strips inside as well!