These are instructions for installing an autodim / compass / temp rearview mirror found in many of the higher optioned base ions. Specifically on a 2004 car
What you’ll need from a donor car:
1. Headliner wiring harness / Mirror
2. Ambient Air Temp Sensor / Pigtail
3) 2 pins with at least 1′ of wire from the body harness connector on the C-Pillar (driver side)
Connector looks like this. You remove the gray insert by sliding it out, then remove 2 of the pins by pulling them out of the back. You will use them on your car later
Wiring harness notes:
The biggest differences I can spot in the harness is the obvious addition of a connector for the power mirror, and additional pins in the C pillar connector on the driver side. The 2 additional pins are for the ambient air temperature sensor readout.
Testing the mirror:
Using the donor harness you can test the mirror power up/compass/and auto dim feature. Plug the connector into the mirror, and plug the other connector into the C pillar connector on the rear driver side. You’ll need to remove the black plastic trim above the deckboard with an 8mm? socket.
As long as the mirror has power/ground these features work as the light sensor and compass are built into the mirror assembly. The only thing that will not work is the temperature sensor feature (for now)
First thing, remove the old mirror. This is accomplished by loosening the torx screw on the old mirror assembly, the mirror slides up to come off.
Install the new mirror on the windshield in the reverse order.
The next part will require you either removing the entire headliner, or getting crafty with the new wire harness. My headliner was trashed, so it came out anyway.
To remove the headliner, just remove the C pillar plastic trim pieces (I think it’s a 8mm bolt under each cap), the a pillar trim pieces, pull back the weather stripping across the top on the driver and pass side, remove the sun visors, and then if you have a sunroof, there will be super strong velcrow attached around the perimeter. You’ll need to stick your fingers in and round the sunroof and pull down, chances are the velcrow will separate from the headliner and you’ll need to glue them back on later.
The clips for back seat area, you need to take a flat blade and pry the center back and out. They are just inserts that press inward to secure the clips.
The seat belt trim slides out towards the outside of the car on each side
Don’t forget there is a tree clip on the center back of the headliner, you’ll need to pull that out too.
Headliner shown here
The original harness cannot be removed, so I cut the connectors off. I ran the new harness along side the original on my headliner, using a glue gun, I adhered the wiring to the backing
With the headliner back in the car, this is what it will look like
The last thing left to do is run the 2 new wires for the ambient air temperature sensor