[Squidward]

I just did this a few weeks ago when I mounted my rear bumper. Funny that the "how" fades into obscurity in just a few weeks.

The housing bolts to the bumper from the back side. If you only needed to change a bulb, I think you could remove the screws on the lens, pull the lens out, and get access that way. But if you need to service a socket, then yes, the valence is the limiting factor. I had to repair a backup light socket last week, tho, and was able to squeeze my hand up behind the valence to get the socket out. I had an intermittent "Fonzie" style lamp, and it required a little bend upward in the electrical contact in the socket so that the bulb had a little more spring tension.

Valence removal might be easier, but I was able to get to it from underneath.

It helped that when I rewired my car I left a little extra slack on my tail sockets. This made servicing bulb/socket easier. But this probably doesn't apply to you.