Check owner's manual. If you don't have one copy and paste link below; www.fleet.Ford.com/maintenance/owners_manuals
how do you change the rear license plate light on a 1999 Buick Regal
How do you change the liscence plate light fuse
see:How_Change_VW_Polo_1999_Number_plate_light
The 1999 Mercury Sable license plate light and the right side brake light are on the same fuse. If the fuse was bad neither brake light would work. The problem probably is burnt out lightbulbs.
License plate light covers for a 1999 Honda Civic can be found at any auto parts store. If the stores do not carry the product, they can order it for the customer.
Remove the cover using a tork bit.
I have a 94 not sure if they are the same but behind the license plate was mine Good luck Answer Improvement (Sept 5. 2010) Remove 4 license plate screws and licence plate Remove 4 hex head screws that hold the license plate/backup light assembly Rotate the license plate/backup light assembly around 180 degrees so you can get to the light bulb holders Carefully turn bulb holders 1/4 and remove bulb holder Carefully remove old bulb and replace with new bulb (#194) Reverse these step to reassemble
All it takes is a straight sscrew driver, Go down by the license plate look up from were the light casing is. You should see a little slot. Put your screw driver up there and push against the ligt casing this should pop it out and it is pretty easy after that!
Rear license plate lights replacement require that you remove the entire frame with reverse lights. Remove the 3 cover bolts on the inside of trunk, remove license plate, remove the for bolts holding frame to tyrunk lid, slide unit down and out and you will have to twist the bulb sockets and remove the bulbs and install in reverse.
Push in & turn the bulb a quarter & should pop out. Get the same no. bulb from an auto parts store.
you buy a new one
# 168 according to the 1999 Ford Mustang owners manual