Blinker problem

My 1999 Grand Prix's right rear blinker won't come on. I've changed the bulb and even replaced the plug when the new bulb didn't fix the problem. I checked the wiring and the light housing and found that there receiving power. Any help would be great. I only have a short time left to get it fixed before inspection.

Did you check the ground?

If it wasn't properly grounded, wouldn't it keep the brake and reverse lights from working too since they are part of the same light housing?

Are you sure the socket has power? 12 volts on one side of the right rear signal lamp should be pulsing since it works off the flasher. Did you measure the voltage with a meter since you suspect the ground is good? It may be a bad contact at the multifunction switch (stalk) at the steering column or wiring between those two points.

I don't have a voltage meter, just a test light. The test light showed that everything was getting power, but without a voltage meter I can't tell if it's getting enough. All of the other lights and blinkers work just fine.

It doesn't matter if the other lights are working, you need a good ground on the socket that's not working. If the turn signal uses a double filament bulb & one filament lights then the ground is most likely good. I'm assuming the right front bulb is working.

Yes the front one is working just fine.

I downloaded a wiring diagram. PM me an email address if you want a copy. It is a double filament bulb. One filament is for the tailight & the other is for the brake & turn signal. Does the right side brake light work?