I looked and looked, and couldn't find a guide for the gen 3 on how to do this, so I thought I'd create it. I did this behind the overhead console, but you could maybe do it between the mirror/windshield. Everything comes apart easier than it goes together, so take your time. This took me about an hour total, with distractions (read: kids).
- Remove the overhead console. Pull straight down from the vehicle front. There's a tab in the rear, along with a giant wiring harness and the mic wiring harness. Pop out the giant wiring harness; this harness has very little slack. The entire mic assembly will pull out of the console.
- There's 2 screws holding the black plastic frame. The harness we're after is clipped to this, so we need to drop it. Pay attention to how you remove it, as the hardest part of this hole thing for me was getting this piece back in there.
- Pull the harness from the wire loom and look for the dark blue and red wires. Red is constant on; dark blue is on with ignition. The dark art of magic pixie wrangling is not my strong suit, so I don't know exactly what the other wires do, so don't ask. I took an educated guess when I clipped these.
- Cut the red wire, and connect the mirror-side portion to the dark blue wire. I used a butt connector, because I thought a t-tap was too big for the space. I also taped off the end of the red wire to prevent any fun shorts.
- Put everything back, clean up, and enjoy a beer.