99Century My license plate and backup lights don't work

Question edited for clarity.
Question moved to model category.

Check where the earth from those lights meets the bodywork.

It is a known issue

https://www.google.com/search?q=2003+Buick+Century.+My+license+plate+bulb+not+working

Fuse Box Diagram Buick Century (1997-2005)

https://fuse-box.info > buick > buick-century-1997-200...

Fuse box diagram (location and assignment of electrical fuses and relays) for Buick Century (1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005).

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hi grace.
this is all i could find.try this link might help you.
how To replace License plate lights on 2003 Buick century Google Search

Check for the presence of power at those junctures. If there then look for a bad ground. If not there you need to find out where the power is being tapped from and check out the fuses/relays in between.

-It burn out. Replace new one.

Mai

They are two different circuits. Do you have voltage at the neutral safety switch when in reverse ? Are the ground wires for the light sockets ok ?

The back up lights may be on a separate fuse from the tail lights. The license plate light should be fused with the tail lights though. The bulbs are good on the license plate light too? Did you have the ignition switch on when you were checking the back up lights? It could be the neutral safety switch is out of adjustment or the switch is bad. Does the car start OK in both neutral and park? If so the switch adjustment is probably good, but the back-up light portion of the switch could be bad. That switch is located on top of the transmission, about right under the master cylinder for the brakes. You have to disconnect the shift cable lever from the trans to get the switch off.

How can I adj. . a trunk light switch on a 02 Buick Century

Does the fuse have power in and out when a test light is used? This test would be run with the light switch on.

yes you will you will have to take side trims and sill panel off get a 10 mm ready and take the bolts out the tail liaghts should come out the license lamps have screws in them and if you looka t them but you should be able to twist bulbs and pull them out / Please rate my response thank you very much