Rear plate lights not working!!

[90GT]

OK so I have a 1990 GT and the rear plate lights aren't working! Every other lights in the rear and front work fine, Its just the plate lights. I put new bulbs in and they still don't work. I had a look at all the wiring that I can easily see without taking all the rear plastic out, it looks fine. Any idea's? A friend said to take all the rear plastic out and check for a bad ground? Not really sure what i'd be looking for though, but is that the next step?

Any help is appreciated!

[ZR]

Test light, check for power and ground in the wires to it.

[ZR]

If your unsure how to test, click on the link below, decent explanation of how to check for power / check for ground.

http://autorepair.about.com/od/troub...rcuit-tstr.htm

[90GT]

^^^^ awesome! Thanks!