Auto-dimming mirror installation on a Saab 9-5.
Some cars came with it,
some without. You can find it in eBay, on scrap yards, or buy it from Saab.
It's a direct replacement, you just need to provide the power for the mirror.
Later cars have an accessory wiring harness to plug the mirror in. If
the harness is not there, you will need to do the wiring yourself.
The only tool required is a Torx/flat screwdriver from the trunk.
If you need to quickly test the mirror, power it up by applying 12V between
the red wire (pin 5) and the black wire (pin 8). Then cover the sensor on the
back of the mirror and point a flashlight or another source of the bright
light at the glass. It takes about 3-4 second to dim, giving the
image a greenish hue.
The wiring used in this guide is specified by the Saab manual for early
style mirrors with no compass and homelink device. It uses an non-switched
power source. Later style mirrors draw more current, so you need a switched
power source (e.g. a sunroof lead) to turn the mirror off with the car and
prevent it from draining your battery.