I'm getting the Position Bulb Failure alert on my 2000 S80, but after inspecting I have all of the following lights working within my tailights:

Both Brake Lights
Both Turn signals
Both Reverse Lights

There appears to be a fourth portion of my tailight that is not illuminating on both sides, but I cannot tell if there is actually a bulb in there or if it is just idle space. If someone can help me shed some light on this it would be greatly appreciated.

Thanks for the help!

 

Try moving the lights around. Could be loose.

 

I took a closer look and found the dead bulb. I didn't realize that the taillight portion had two bulbs in it instead of one. I took a look at the owners manual and tracked down the culprit. Thanks for the help though!