The passenger side mirror has ambient temp sensor, and mine went bad probably around 20k miles. The bad ambient temp sensor can cause some AC related issues, or even CEL (like P0071 and/or some other). Those things just pops up randomly, particularly when the temperature changes rather dramatically. I just erased the code and off merry way till it pops up again. At 100k miles, I finally decided to fix it, bought an inexpensive after market mirror. It's about 1/2 the price of OEM, and everything works, but those cheap after market mirrors, the mold is just slightly different and you can't use the OEM cap. Unpainted cap comes with it, so that's sort of fine. Fit and finish is not great either, worse than OEM, which is an achievement (had to file down the back side slightly to make it fit properly). Just thought someone here might wanna know.