**2003 Mercury Sable: Passenger Side Tail Light Out
 

I have a mercury sable 2003 with the passenger side tail light out. I thought it was no big deal cause the filament in one of the bulbs was burnt out, so I replaced it. After replacement though, both lights are still not lighting up.

Any ideas on what steps I should take to fix this now ? Need a little help, thanks to those who can offer some!