Electronic auto-dimming rearview mirrors, such as Gentex Homelink mirrors, can really come in handy if you don't want a lot of glare on your mirror while you are driving. The tradeoff is that these mirrors need to be wired into your car. The good news is that you can do this yourself, even if you don't know much about car maintenance.
Use your screwdriver to remove the screws at the base of the rearview mirror currently installed on your windshield.
Slide the base of the mirror up out of the mount connected to the windshield and set the old mirror aside.
Run the HomeLink mirror wiring coming out of the back of the mirror along the inside of the roof of your car and down the side to the dashboard. You can use electrical tape to secure the wire to your roof at intervals for a temporary way of attaching the wiring. If you don't mind spending a little more time on the project, you can carefully cut a slit in the upholstery of the car's ceiling and run the wire through so that it is concealed.
Locate the fuse box of your car according to your car's user manual. On most cars, the fuse box will be under the dash of the car. Remove the screws on the part of the dash that is covering the fuse box. Remove that part of the dash to access the fuse box.
Remove the screws on the front panel of the fuse box to expose the actual fuses.
Connect the two color-coded mirror wires to the ports on the front of an ignition-based fuse. This is a fuse that controls electronics which start when the car is turned on. The location of these particular fuses will be listed in your vehicle's user guide.
Replace the fuse panel and dash panel. Turn on your car's ignition to test the mirror. You will notice the mirror begin to adjust with the available light.
