Installing An Auto Dimming Rearview Mirror
Ever wonder why General Motors would sell a $30,000 plus car and not offer an auto dimming rearview mirror as an option? Well I did too, and it is a feature I've liked in other cars.
Here is the good news, on a scale of 1 to 5 (one easiest and five the hardest) this project is about a zero (how is that for easy).
1) Source your mirror. You have a couple of options JHP sells them right now for $195, new official GM part. Your other option is out of a wreck. Now obviously a wrecked G8 is not an option so what you're looking for is a 2007 Chevrolet Trailblazer, GMC Envoy, or Saab 9-7X. Other models years may work. You ultimately need compass, air bag indicator, OnStar and of course the auto dimming feature.
If you order a rearview mirror with both temp and compass display, the temp display will indicate an error message. You can perform minor surgery to cover up this part of the display but there is no way to get the temp to display on the mirror.
A used mirror will cost $50 to $75 on average from a junkyard or online part distributor. Make sure they certify they ship it in working order.
2) So now you got your mirror. What else do you need. Well simply a 15 torx driver. That's it.
3) Got your mirror and your torx driver. Swing the mirror up, so that it is pointing up toward the roof console, this will give you some room to work. Look at the base of the mirror where it attaches to the slug on the windshield (more on that in a minute). You should see a single torx screw. Go ahead and remove it, careful it doesn't drop, nothing worse than trying to find that jet black screw in your jet black interior.
Slide the old mirror up, moving parallel with the windshield, it will slide right off a metal slug that is attached to the windshield. Do not pull the mirror toward you, you want to slide it up toward the roof, it should just slide right off. The small black cable cover will probably drop to the floor, no issues and we'll get to that in a minute.
Turn the mirror around there is a single wiring harness attached to the back. Squeeze the retaining clip and it should slide right off.
4) If you got a new mirror from JHP, keep the black cable cover, if you didn't it, you won't be using it for the new mirror install. First slide the mirror onto the slug (I find this easier to do before attaching the harness). Attach the harness (don't attach the screw yet). The following should happen basically all at the same time. The airbag system should self test, showing both the on and off indicators, and unless there is someone in the seat, should then show the off light. The display for the compass should also self test with all LEDs lit for a second, and then show whatever compass direction you're facing. There should be two green LEDs one to the left of the power button (where the compass button use to be on your old mirror) and another one to the right of the OnStar emergency button. The one on the right is for OnStar, just like your old mirror. The one on the left is for the auto dimming feature. If it is green, it is on. If you have OnStar push the blue OnStar button, confirm with the operator that they can hear you (and you can hear them). Congrats! Your seconds away from being done.
5) Reattach the torx screw into the new mirror. Careful not to over torque. If you have a mirror out of a different GM vehicle the cable cover won't stay in place. You can change the angle of the mirror neck so it sits higher on the windshield, covering up most of the cable. Its well wrapped in cloth anyway and was partially exposed to being with.
Congrats, you just did a $400 job at the dealership!
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Originally Posted by Zodiac
