Tail lights and blinkers don't work?

I have a %26#039;94 Buick Regal Gran Sport. After recently changing the alternator in it, my tail lights and blinkers stopped working. I%26#039;ve tried changing out the fuses, but that didn%26#039;t help. What else could it be?|||Multi Function Switch.|||if it happened right after hooking a charger to the system you more than likely blew some fuses or relays