Just did this on my 1998 Mazda 626 ES it goes as follows:
-From the outside of the trunk look above the license plate.
-Use a screw driver to pry out the light fixture by sliding it left or right then tilting it out of the hole.
-From the top of the light fixture twist the bulb assembly out of the fixture.
-If the auto shop sold you the whole bulb assembly then just twist the new one back in and you are good.
-If the auto shop sold you just the bulb, you need to unhook the bulb wires off of the bulb assembly and even scrape them off of inside the metal plate they are hooked around to get the bulb out.
-Unbend the wires on your new bulb so that they stick out below the bulb.
-Insert the bulb straightened wires first into the assembly.
-From the back of the assembly where the wires now stick out, bend the wires over the metal plate in the same fashion that the old ones were.
-If you have some solder it won't hurt to tack this wire down. I didn't and my lights work (so far).
How do you change the liscence plate light fuse
How do you install a rheostat in 1999 626 Mazda?
http://www.acehardware.com/product/index.jsp?productId=1295875&cp=&pg=2&sr=1&origkw=license+plate&kw=license+plate&parentPage=search&searchId=22063708833
how do you change the rear license plate light on a 1999 Buick Regal
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.
see:How_Change_VW_Polo_1999_Number_plate_light
you buy a new one
# 168 according to the 1999 Ford Mustang owners manual
Open the trunk, then remove the 1st and 2nd rows of black liner insert pegs. The color of the pegs may vary. Lower the trunk liner enouph to see the inside of the license plate lamp. Remove old lamp and install the new one. The job takes about 15 mins.
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.
Open the trunk. Turn the socket counterclockwise and remove. Then gently pull out the light bulb. Place the new bulb in the socket and replace the socket into the lens by turning clockwise. Replacement light bulb #3652.