I had installed one in my 4.3 that I liked it much enough to put one in my mom's 4.2 Base. She doesn't need to fiddle with the garage door openers at her home or my home anymore. It was bought off eBay from a Nissan vehicle since it had the amber compass display. It's a Gentex 453 with a 3-wire pigtail consisting of: 12V constant, 12V switched, and ground. I extended the wires and sleeved them up.
Step 1: Remove two screws in the holder.
Step 2: Use a pick to remove the map light cover and remove the screw.
Step 3: Pull down the overhead console at the end closest to the windshield, then slide the console toward the windshield to remove it.
Only two wires were exposed, blue/red = 12V constant, white/black =ground
Step 4: Add t-taps to the wires and attach the spade connectors.
Step 5: Since there was no 12V switched in the overhead, run a wire down the a-pillar to the kickpanel.
Step 6: Find the 20-pin connector and exposed the black wire, which is 12V switched.
Step 7: Add the t-tap, attach the spade connector, and tidy up the area.
I tested everything to make sure the mirror, compass, and homelink were functional before putting the console and panels back together.
Went to get me a 453 today from the wreckers from an Infiniti SUV. I also saw a 04' or 05' Rav there and decided to practice taking that mirror off as I had no idea how to do it...
Mine looks like this, same one gladerunner4WD posted a picture of in his build thread...
The one at the wreckers was different so when I got home to do the mod I was thrown off but thanks to the pic provided by gladerunner4WD I could see that there is a tab there that needs to be pushed in and tried a small flat head screwdriver but that was awkward so I just pulled up and towards myself and it came right off.
The one at the wreckers was different so you may have the one that I saw there and not what I have. Here is a pic of what mine looks like on the windshield. The other one I saw only had a small slit like where I put the red arrow. The small slit is for you to stick a small flat head screwdriver or something in there to bend the metal retaining clip on the inside. Just bend straight or slightly towards you and it should slide off the metal backing plate. It must be a different design, older or newer, 3rd party, who knows..
What you're trying to do with either one is to get it out and over the grooves on the small metal plate that's glued to the windshield as seen here.
Anyhow, I hope this helps anyone else trying to do this mod.