From experience...2004 Limited (the only flavor that year)...when I installed LED's to brake and turn signals, and re-wired the back-up to strobes, the auto-dimming function quit. I traced it back to the body control computer, which "tells" the rear-view mirror when to dim or not. It does this by sending 12V signal (hi = Dim, <12v no-dim), so that dimming is off when you shift into reverse...Idiot computer figures bulb is "out" so it inhibits dimming. I had to put 12V on input "manually" by routing 12vdc through a switch I installed in map light housing. Now the mirror dims as it should, automatically, based on light coming in to front and rear photoeyes. The electronics to control dimming is in the mirror housing, but the 12VDC to enable it comes from body computer. Hope that helps...ctsemicon "Dad's out in the garage playing with his toy again".