Chevrolet Repair: Electrical problems, 1978 buick electra, buick electra

Question
I have a 1978 Buick Electra overall in very good condition, but recently I've been having some electrical problems, I've been told that era of car style basically are the same (i.e.) Chevy's,Buicks,Olds,etc.  First off my interior/door/dome lights will not go off unless I take out the fuse, and my parking lights will not go off unless I disconnect the battery. I've been told to check my fusible links,relays, and circuit breakers but I'm having a hard time finding them. Could you help me understand this problem and if its links,etc could you help me locate them, I'd greatly appreciate it.  

Answer
Mark ...Lets go right to the source. The circuit breaker for the headlights is built into the light swich.You probably have a short to ground in the switch, which will keep the interior light on. All interior lights are ground circuits. The bulb receives 12 volts and the doors ground or your ''twisting'' of the light switch grounds. I would look in the area of replacing that switch...Best