Have never attempted so I am just thinking out loud here but...Not sure how the added draw would cause any issues as if that where the case the added draw caused by turning on the dome lights would cause an issue. Then there is the question of what the issue would be. Doubt a self dimming mirror draws enough juice to blow a fuse. One thought that comes to mind regarding the suggestion that you can hook up a radar detector to the harness in dome light is that that only works if you have a self dimming mirror because it uses switched power not constant like the dome light. If you have a sunroof that switch should have a source of switched power.

 

I have them but would never order them. I have tinted windows and with them engaged at night I can't see anything. I have them in my other car as well and turn them off there as well. Just another gadget to complicate things and fail.

 

I have 15% tint on the back window which effectively takes the place of a self-dimming mirror. I rarely use the lever to darken the mirror anymore unless a big truck's headlight gets lined up just right in my mirror (granted they occasionally seem to enjoy doing this).

As an aside to an earlier comment: My radar detector connection uses a wire that runs hidden along the headliner and down the front pillar all of the way down to the fuse block and uses an aftermarket fuse box adapter to plug into an unused fuse position that switches with the ignition. I think this is typical since no splicing to existing wires is needed and it introduces no loading problems on other circuits.

 

Just read a DIY for installing a Valentine radar detector hot wire tapping in to the Home Link wiring. This was posted by bonehead back in 2010. Since this would be a switched lead, and is in the right location, doesn't that sound good for powering up a self dimming mirror?
I think this is what I am going to do, and will post pic's as I do both the mechanical switch of mirrors and the wiring.

 

I hope someone can help me here.
I received the auto dimming mirror from the wreck in Australia and it looks like it is in good working condition.
However, the electrical connector is a 5 pin (see attached photo). I figure the reason for so many pins is that the factory install uses the sensors from this mirror to control the dimming on the 2 side view mirrors. I don't need to worry about that. But how do I know which pin is the hot one, and which is the ground (or is the ground just part of the mount)?
Please any help or suggestions is most appreciated.

 

Homelink wiring diagram from a 2005 997 attached

 

Just a disclaimer: All of this could be wrong, and if you provide power to the wrong pin you could burn out the mirror circuitry. If you have a good relationship with your dealer's service shop, maybe they could help. They should have the wiring diagrams.

That said, I decided to poke around the web for an answer. I like a challenge. The closest thing I've found was this for a Boxster - which probably uses the same mirror (text is directly copied and pasted)I also saw a posting saying that the mirror is made to brighten when the car is in reverse, so that explains A3. Don't trust me on this, but I'd guess A4 is power and A5 is ground (not unusual for the ground wire to be green). Another wild guess is that A1 and A2 provide the signals to dim the exterior mirrors.

Now if you can figure out which post is which connection. Sometimes they are small labels if you look closely... just hopeful thinking.

 

Another thing I've discovered is that the mount of the base to the windshield may be different for auto-dimming vs non-auto-dimming. You might want to check to see if you have a mounting problem before proceeding further. Hopefully I am wrong. Maybe the difference is related to the rain sensor.

In any case, I'd suggest you check the base first to see if it will even mount.

 

I'm not sure about that. From other German car wiring specs (VW's I've worked on for 20 years) TERM 15 may provide power and TERM 31 may be ground. One is switched power (I think Term 15 black-orange, likely switched hot when the care is not in deep sleep mode, and one is to ground (I think term 31 - brown ).
Actuation - yellow wire and green wire - are signal lines or something.

Remember the mirror has a location-light(ambient low power light) that is on and powered independently of the mirror dimming, so there needs to be power provided by a source that is not the dimming feature.

 

because they can...

 

So I was going to check the mount to make sure the auto dimming would fit, and if ok was going to start today and hopefully finish before the start of Super Bowl tomorrow. But all the talk about a rain sensor is giving me pause. I know my car has a rain sensor somewhere because my wiper blades are speed sensitive based on the amount of rain falling. But I never thought that might involve the rear view mirror. Could someone expand on this topic? Thx.

 

I decided to dig a little more just for grins.

There are four different part numbers for rain sensors: coupe with auto mirror, coupe without auto mirror, cabriolet with auto mirror, coupe without auto mirror. I can't tell why there are four from the info I've found. I'm not sure if the mount is different, or if it is just the wiring connectors, or possibly the wiring channel itself.

This website shows the four combinations best (look at the four part 6'es in the list): http://www.gaudinporscheparts.com/pa...agramCallOut=6 Since it didn't show the part numbers, I hunted them down on AutoAtlanta, they are: 99761269300, 99761269325, 99761269400, and 99761269425.

If the mount is the same you are in better shape but you may still need to hack the wiring. Then there is the question as to why there is a difference between coupe and cab. Did the mirror come from a cab?

You can try removing your existing mirror to see what the differences are, of course I would be very careful because you don't want to accidentally break the cover (other posts talk about people doing that) or pop off the rain sensor from the glass and create more work and cost for yourself even if you don't end up changing. There is a mirror DIY for automatic mirrors at https://www.6speedonline.com/forums/...ml#post3584448 if it helps you understand how a typical auto dimming mirror is mounted.

I'd suggest you ask your dealer's service advisor if you can ask the techs about it. Good luck and let us know how it turns out!