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-   -   Upgrading to Auto-Dimming Rearview on 991.2 (https://rennlist.com/forums/991/1032215-upgrading-to-auto-dimming-rearview-on-991-2-a.html)

2001f4s 10-29-2017 09:48 AM

Upgrading to Auto-Dimming Rearview on 991.2
 
Can anyone comment on the feasibility of upgrading to an auto-dimming mirror on a 991.2, Kind of missing this function from my 991.1. I haven't looked under the interior light panel but assume the connection is there. Any input or experience would be appreciated.

The Ox 10-30-2017 10:31 PM


Originally Posted by 2001f4s (Post 14566742)
Can anyone comment on the feasibility of upgrading to an auto-dimming mirror on a 991.2, Kind of missing this function from my 991.1. I haven't looked under the interior light panel but assume the connection is there. Any input or experience would be appreciated.

+1. I'm 10 days into mine (picked it up 10/20), from an '09 S , and I really miss the outside mirrors dimming. I don't mind manually adjusting the interior mirror, but with modern headlights, I find the outside mirrors too bright. Porsche should make this standard.

BlackCS 10-31-2017 12:09 AM

There is no connection, I sold my 911 and purchased a Cayman, which also doesn't have auto dimming, I ordered a used one on ebay. I haven't been able to get it to work yet, but from what I was able to work out so far, there are 3 wires, one - one + and a signal wire, which is sometimes designated as the reverse wire. I'm going to test to see what voltage is applied to the signal wire, which tells the mirror its okay to start dimming. It's also called the reverse wire, because at night, when the signal wire is activated and the mirror can dim accordingly, when you go into reverse, the mirror reverts to day time mode, where it cannot go dim, in order to improve visibility. Trial and error but I'm positive I will have it working soon, just haven't had the time to figure out the proper voltage, but there doesn't appear to be anything complicated in the system.

2001f4s 10-31-2017 02:13 PM

White981s excited to hear your findings. Thanks for the responses

The Ox 10-31-2017 08:23 PM


Originally Posted by 2001f4s (Post 14571777)
White981s excited to hear your findings. Thanks for the responses

Correct, me too. Thanks, appreciate the info. I am REALLY hoping I can update. Not overly concerned with the cost. I amortize items over their life time, and this is one I want. A little, (a-lot) of rationalization...

12v Nick 10-31-2017 08:59 PM

Most European auto-dimming mirror circuits are self contained and only need power and ground to function. It should be as simple as identifying the pins and connecting them to the correct circuits. I was curious on the 991 so I looked up the wiring for what Germany calls the "Anti-Dazzle" mirror circuit. Here's what I found:


https://cimg9.ibsrv.net/gimg/rennlis...1bd67117c7.jpg


If you look at the Interior Anti-Dazzle Mirror at the lower left you can see it has a 5-Pin connection. The only two wires you actually NEED are pins 1 & 2 which are ACC power and ground. Pin 3 is labeled as "reverse" and I assume that will override auto-dimming when backing up for safety. That should definitely be connected as a precaution. Last two pins look to be sync wires for connecting to the left and right dimming side mirrors. Assuming the car doesn't have that feature if it was missing the interior AD mirror, so no need to make connections there.

If I were attempting this install, I would buy these two parts:

Auto-Dimming Mirror: https://www.sunsetporscheparts.com/o...MtOGwtaDYtZ2Fz

Wiring Harness: https://www.sunsetporscheparts.com/o...MtOGwtaDYtZ2Fz

There's a chance that the receptacle for the wiring harness exists in the headliner and it's am plug and play setup, but if not, at least the harness would give you the proper plug, wiring colors, and pin out.

If anyone tries this out I'd be anxious to know what your results are. Furthermore, if anyone IS trying this out, feel free to reach out to me for any assistance I might be able to lend!

–Nick

BlackCS 10-31-2017 09:10 PM

Nick, great catch on the wiring harness, that may actually work. I still haven't had a chance to look at it in depth, however it appears to be rather simple in operation. According to the wiring diagram in the link you provided, the rear view and rain sensor feed of the same loop, which makes sense since the rear view mirror and rain sensor connectors look almost identical.

I think the rain sensor works the same as the rear view mirror, where the headlights have to be ON in order for the rain sensor signals to activate as well as the mirror to begin dimming.

Anyway I'm going to open the overhead cover and check to see if I the harness is indeed modular, if it is, this should be an easy retrofit.

2001f4s 10-31-2017 10:19 PM

Nick,

Great information. I am going to give it a go, and I will report back.

Rocket_boy 10-31-2017 11:03 PM

Couple things to remember here though....

The interior mirror is just one part of the mirror dimming system. It contains the sensor, switch and dimmable glass. I believe the two exterior rear-view mirrors use different glass (and part numbers) for the feature. If you did not order auto-dimming mirrors you did not get the dimmable outside glass. So while the interior mirror may properly dim when in use, it will not make a bit of difference to the outside mirrors.

You could possibly change out the door mirror glass to the correct part, but looking at the parts catalog the wiring harness looks to be different also.

Good luck with whatever you attempt,....worthwhile looking into......

BlackCS 10-31-2017 11:52 PM

Yeah I'm well aware about the outside mirrors, not going to mess with that, especially since I'm getting tint's installed. I checked the voltage on my cayenne's rear view mirror, basically the signal wire is receiving around 4.5 volts when activated, the rain sensor signal wire was giving off around 3.8, I tried a jumper for that line to the mirror and no go, probably not enough voltage. Now I just have to find a proper trigger line with required voltage.

Noah Fect 11-01-2017 04:41 AM

IMHO the outside mirrors are hazardous at dusk, especially in the rain, when half the cars around you are driving with their lights on and the other half aren't. They get way too dim, leading you to think you have more situational awareness than you do.

It's nice to have the dimming feature on the interior mirror, but I've been really tempted to disconnect the wires going to the exterior mirrors.

2001f4s 11-01-2017 07:32 AM


Originally Posted by white981s (Post 14573161)
Yeah I'm well aware about the outside mirrors, not going to mess with that,

+1

Rocket_boy 11-01-2017 11:22 AM


Originally Posted by Noah Fect (Post 14573427)
IMHO the outside mirrors are hazardous at dusk, especially in the rain, when half the cars around you are driving with their lights on and the other half aren't. They get way too dim, leading you to think you have more situational awareness than you do.

It's nice to have the dimming feature on the interior mirror, but I've been really tempted to disconnect the wires going to the exterior mirrors.

I have them, but for me it is a different issue. With the back window tinted,....the sensor gets the wrong information and "thinks" oncoming lights are actually not that bright,.....so it never really triggers the outside mirrors to dim much.

I wish Porsche would put the sensor somewhere else,....maybe in with the rear camera so no interior factors would affect it,....or make the effectiveness adjustable through PCM.

eecsdude 11-27-2018 08:03 PM

this is an old thread, but wondering if 2001f4s was able to get this retrofit to work.

RYE 11-28-2018 01:43 PM

https://cimg4.ibsrv.net/gimg/rennlis...30208120f0.jpg
I replaced my 991.1 mirror with the 991.2 version. There are only three wires. Switched 12V, Ground, and LIN. Here's the schematic for my car.
I doubt the mirror will work without LIN connection. The mirror needs to know if the lights are switched on, it feeds from and communicates back via LIN.


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