Installing a Gentex GNTX 177 Rear view mirror

A couple caveats: Mine is a '95 X300, and newer models have different mounting buttons and wiring pigtails. In my case, the auto-dim & adhesive holding the mounting to the windshield both failed. To disconnect the mirror assembly from the OEM mounting button, rotate the entire assembly 1/4 turn, pivoting on the button at the top of the windshield.

Here is my step-by-step:
Open the ceiling console by turning the lock screw inside the sunglasses compartment 1/4 turn. Pull the console straight back, parallel to the roof line. Disconnect the wire connector & set the console aside.

Disconnect the mirror wire connector, and the old mirror is free. At the top of the adjustment arm, at the entry of the wire pigtail, use a small screwdriver to pry off the cover from the arm, allowing you to cut a longer lead, if necessary.

Removal of the old button is problematic. I'm advised that applying heat (hair dryer) often softens the adhesive enough that using a razor blade to "scrape" against the windshield works. Extreme caution is advised. Anyway, my button was already off, so scraping the remaining adhesive was no problem. Mark the new button location on the outside of the windshield with a felt tip pen, about 3" below the OEM button. Attach the button to the windshield following the instructions that came with the adhesive (available at any parts store for about $3).

Run the wiring from the overhead console to the temperature probe. I discovered that there is enough space between both the headliner and the pillar cover without removing either. I used speaker wire (because 1 lead has a tracer) although I believe that lamp wire would also work. I also discovered that the wire will also fit under the junction of the pillar cover and dashboard, becoming exposed inside the door jamb near the weather seals between the door and pillar. A used piece of a door edge protector to cover the wire inside the door jamb acts a weather seal. The wire then runs under the corner of the fender & under the cowl cover, to the corner of the 2 hood (bonnet) weather seals. From there, it runs beneath the wire cover along the side of the fender to a small opening to the underside. The temperature probe was attached inside the fiber bumper cover at one of the screws connecting that cover to the splash shield. It is important to locate the probe outside the engine compartment, yet out of direct wind.

Connect the wires (using butt connectors) at the ceiling console & temperature probe. In the X300, slate/grey is 12v+, green/red is reverse inhibitor & black ground. On the Gentex 177 mirror (with a 7-pin connector) pink is 12v+, light green is reverse inhibit, black is ground, grey is auto-dim left outside mirror dim, pink is right outside mirror dim, dark green/white is temp probe & black/white is temp probe. The 2 outside mirror wires weren't used in my application. OK, there are 2 pink wires. I used my lawn mower battery to test the mirror prior to installation to determine which pink is 12v+.

That's about it! No holes drilled, no alterations made to any components & I didn't even have to remove any interior components, except the ceiling console.