The following tutorial describes how to install a Gentex GNTX-221 Auto-Dimming, Compass mirror with map lights from an Olds Intrigue. I have this mirror installed on my Reatta. I think it'is a great rear view mirror upgrade for the Buick Reatta.
This tutorial applies the the Auto-Dimming mirrors that have the 7 pin connector on the rear. It assumes you have already removed your Reatta rear view mirror.
A tutorial that covers Compass mirrors with the 4 pin connectors can be found here: Compass Rear View Mirror Install Instructions
Here is another site that I find helpful when installing mirrors: Everything you ever wanted to know about auto-dim mirrors!
1. Make An Electrical Adapter
You will need to make an adapter to connect the Compass mirror to the Reatta electrical connector. Follow the simple instructions below for making the adapter. You will need the connector and some of the wires from the GNXT-221 mirror so be sure to get them included with the mirror when you purchase it.
Wire colors may not be the same in all 7 pin mirror connectors that you will find. I have seen them with all black wires but no matter what the wire colors are they will still work if they have the same pin configuration as the connector shown below. Note the pin numbers listed beside the connector.
2. Install The Compass Mirror
Plug the electrical adapter you made into the back of the mirror. Secure it to the shaft of the mirror with a small plastic wire tie as shown in the photo below to keep the strain off the mirror plug.
Mount the mirror on the windshield
The GNTX-221 mirror does not use a set screw to hold it in place. The mirror bracket just slides over the puck glued to the windshield. It locks in place with a spring clip at the bottom of hte puck. It takes a lot of downward pressure to lock the mirror in place and it requires a small screwdriver to press down the spring clip to remove it.
I didn't push down hard enough on the mirror for the spring clip to latch on the puck. I don't want to take a chance of the windshield breaking while installing or removing the mirror. Don't say I didn't warn you.
The photo below shows a mirror with a puck still locked in place. I had to remove it before mounting the mirror on my windshield.
Next plug the the electrical adapter into the Reatta's factory mirror electrical connector.
3. Calibrate The Compass Mirror
If your compass mirror reads "SW" all the time or doesn't seem to read correctly you will need to calibrate it. Here is how to calibrate the GNTX-221 compass.
Find an empty parking lot with no cars around to calibrate the compass.
1. Start the car and be ready to drive the car in circles. 2. Depress and hold BOTH map light buttons for a few seconds until a number will appear in the compass window. Then release the buttons. That number is the Zone that the mirror is calibrated for. Mine was set for Zone 8, which is the factory default setting. Zone 9 is the proper Zone for me here in Tennessee but zone 8 seemed to give a more accurate compass reading when compared with my handheld compass.If you want to change the Zone, press the right map light button to go up, the left button to go down. I believe that there are approximately 14 zones across the USA. Lower numbers are toward the Western states. Higher numbers are toward the Eastern states.
3. Next, Hold BOTH buttons till the number disappears and a "C" appears. That "C" is CALIBRATE. You may see the zone number appear again before you see the "C" appear but keep holding and it will eventually appear.4. Drive slowly around in a tight circle at less than 5 MPH. After three laps the "C" should disappear, and a compass point should appeare. The mirror is should now performing corrrectly. If it is still not reading correctly repeat the above procedure and make the tight circles in the opposite direction as you did the first time.
Your Done!
