Ever since I found out that '04 was the only year that came with an auto-dimming rear view mirror, I've thought how unfair that was and that I wanted one! So I found one on eBay and set out to make it work.

The first step was to remove the dome light assembly - a simple task. Just use a flat plastic tool to pry out the cover:



And pull out the 2 screws holding in the assembly:



Which leaves you a large hole that gives you access to the universal garage door opener wiring:




I originally took out the garage door opener because I had heard that all the wiring for the auto-dimming mirror was already in the '05 and up models, and I was looking for a connector somewhere to plug the mirror into...no such luck. The only wiring in the headliner is for the garage door opener.

The next step is to remove the old mirror. The manual says to use a 5mm metal rod, but I used a 3/16" allen wrench that fit very well. You insert the wrench into the hole in the base and rotate the base 90 degrees:



This is what it looks like off the window:



A small round bracket stays on the glass and luckily it is the same part for both mirror styles.





Now to put the new mirror on - you have to thread the wire assembly under the edge of the headliner through to the hole that the dome light assembly mounts into. The mirror goes on the glass the reverse of how the old one came off. This was the hardest part of the job - the casting of the mirror base is slightly different between the auto-dimming and regular mirrors. It's hard to describe how to put the mirror back on...you have to line up the mirror base on the bracket, then keep pushing on the mirror base towards the headliner as you rotate it to lock it in place. It took me 4 tries to get it to lock in properly - you can tell when you get it right because the base is very solid against the glass.

Now that the new mirror is attached, it's time for the wiring. The auto-dimming mirror just uses 3 wires: power, ground and a signal from the reverse lights. '05s and up have switched power and ground, but no reverse signal. The reverse signal is used to turn off the auto-dimming feature when you put the car into reverse to help you see better when backing up at night. So what I did was connect the switched power and ground, and put in a small switch on the power line to turn off the mirror manually if necessary. Here is a wiring diagram:



And a pic of how I wired in the new mirror:



Luckily, the place I got the mirror from (eBay seller) sent me both ends of the connector, so I was able to wire in the mirror and still be able to unplug it if necessary.

Put everything back together and VOILA! To test it, turn the key to ON and cover up the light sensor on the back of the mirror (the non-mirror side) - this should make it go dark.




It is amazing how much nicer it makes driving at night! It was definately worth it.