Auto-Dimming Rear View Mirror - Wire Colours!
 

Bought an auto-dimming rear view mirror from our sponsors quite some time ago, and finally decided to investigate fitting it. Had a look at my existing mirror and the connector type it has. That leaves me with a small 6-pin connector with six wires. I've read through this other thread:

http://forum.a8parts.co.uk/showthread.php?t=1100

but the colours of the wires are completely different. I've also printed out the relevant section from Elsa showing the wiring diagram and the colours listed in that are also different. This is the colours I have on the plug:

1 - Pink
2 - Black
3 - Orange
4 - Red/White
5 - Black/White
6 - Blue/White

Elsa shows the colours as:

1 - Black/Blue - Positive connection
2 - Brown - Earth connection
3 - Blue/Red - Reverse
4 - Red - Mirror motor
5 - Brown/Red - Mirror motor
6 - Red/Green - Front interior light and front reading lights

Going by the Elsa diagram, it looks like pins 1 and 2 are the ones to use, so I'll jury-rig that up to see if it works. Not worried about the other features.

Rather than just splicing the wires directly, can anyone identify the other plug type that I would need?

Sean, I did this ages ago on my old PF S8 (see comment in signature) and it wasn't really difficult. Documented it here somewhere I think.
Remind me, is your A8 PF or FL? (I ought to remember really... :o ) EDit: OK, it's FL, as your signature says.

The main thing I did (which applies to either) was to work out which wire was which and then test it off the car with a 12v DC supply, of which I have masses left over from dead IT kit - routers and the like. Multimeter was handy for that too.

That doesn't make sense, assuming it's a FL interior mirror you have.
The electrical functions that my dimming mirror has are:
1. Left reading light
2. Right reading light
3. Dimming sensors and dimming mirror
4. Feeds to exterior mirrors to dim them
5. Red downlights when the sidelights/headlights are on.

Given there's probably a control unit in there for the dimming it will need positive and earth.
The external mirror control could be one wire or two.
The reading lights can be switched separately by switches NOT in the mirror so that's at least 2 wires as well.
And the downlights would need a separate feed. Given that's linked to the car lights it may be ideal for the dimming power.

A bit of testing on the car should indicate most of those. Does the standard mirror include the reading lights?

Finally, I do wonder if there is already power anyway even if a non-dimming mirror is fitted? So maybe just plug and play? Or are you missing a plug?

My PF install needed power as the PF standard mirror is just passive.

The missing plug is specifically for all the dimming features, but being a FL, it doesn't have it. So long as I get the auto-dimming part working, I'll be happy with that, so shall break out the multimeter tomorrow and have a play.

Photos might help, but if I understand you correctly your standard mirror has a single plug (how many connections?) but the new auto-dimming one has two plugs, the extra being small with 6 wires?

As I mentioned long ago (actually in the thread you linked to) the auto-dim interior mirror only really needs power and earth. Power from a "lights on" circuit would be ideal and you probably have that available already if you can identify it. And earth should be simple.

Correct. The single plug has four connections and plugs into the reading lamp section. I'm opting to go the non-OEM way and just go with the + and - wires.

Hopefully the reading lamp section gives you (for the nightime downlights?) the power you need to tap into.
Multimeter to the rescue.....

Never quite sure how a lot of those minor lighting circuits work, the reading lights will go back to a controller of some sort and may well switch the earth side so I'd try to leave them alone.

The two I did (both long gone) were slightly different but neither bothered with the reverse feed; the S8 I tapped into the sunroof circuits for power (they go dead soon after ignition off) and the Focus I used dashboard nighttime illumination.
The nighttime illumination logically seems a better choice.

Well, finally managed to wire up the mirror... and it works +++

Rather than relying on the cable colours, I just used the pin assignments as described in Elsa, the important ones being:

1 - Black/Blue - Positive connection
2 - Brown - Earth connection

I didn't bother with any of the other options.

Many thanks to Andrew and everyone else that posted in the Auto-Dimming Mirror thread. Very informative.

http://forum.a8parts.co.uk/showthread.php?t=1100

Excellent, where did you get power/earth from Sean?

Took the power from the five pin plug going to the sunroof controls and earthed it to a point right at the front, just left of centre. As you said in the other thread, it's a tight squeeze, and I also had the wire for the heated screen running across.

At least it's one less job to do. :D