Tail lights dont work need

TENGO UN FREESTAR 2005 MINI VAN Y LA LUZ DE LA LICENCIA NO ENCIENDE, NO HAY CORRIENTE EN LOS CABLES, LA CAJA DE FUSIBLES EN SU INTERIOR TIENE UN DIAGRAMA CON NUMEROS, PERO COMO COMPRE LA VAN USADA NO TENGO EL MANUAL DONDE INDICA LA FUNCION DE CADA NUMERO DE FUSIBLES

I have a 2002 f250 crew cab. i recently had a sterio system installed and think they may have wired into something???? At first I would be driving with lights on and my gage cluster(dash gages) would black out(no light in dash) radio would stay on as well as my head lights. but my tail lights, fog lights, cab lights, running(under door) lights would go out. i checked fuse and it was blown so would change and be ok. now my gage cluster(dash lights) work fine and my head lights are on and my radio is playing but tail,fog etc are not working. checked fuse and it is fine. wtf???? someone please help. I am on the road a lot for work. tired of driving with hazzards on. sharky54x@hotmail.com or 713-208-4740

My car stereo and the roof light doesn't work.

headlites nor tail lites not working. Have signal and brakes lites. changed dimmer and inside pull switch also checked fuses. What could be the problem? Where is the lites relay switch located on 1990 f150 p/u truck? Please help. Leon

I have a diagram on my fuse box but it doesn't tell me which fuse is for what.I bought the car used so it doesn't have a manual.