So the "Tail Lamp Failure" light came on recently and I discovered that my drivers side rear upper (above the reverse light) bulb was out. I changed the bulb with a spare bulb I had and it still wasn't working so I bought a new package of bulbs and still no go. I confirmed with a 12v source that the replacement bulbs are working, so I know it's not that.

I looked at the socket and wires with a flashlight and didn't see anything unusual. I also looked for a fuse that might control that one bulb (unlikely, I know), but came up with nothing.

Any thoughts?

2001 LS430 UL

 

Should not be a fuse for one tail light.
Did you use a Lexus bulb to replace the bad one? There was a thread here saying the correct bulb is a must as the car thinks a different bulb means a bad bulb.

 

Make sure you bought the right bulbs. Top and bottom bulbs are different. I usually get them from autozone.

 

So it turned out that I was looking at the wrong bulb. I had pulled out and replaced the blinker but it was the little bulb as yuri.ber noted.