Internal mirror wiring for dimming mirror

steamship · #1 7th July 2021, 03:22 PM

This is the thread that I referred to when I fitted mine:

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

pete-p · #2 7th July 2021, 07:27 PM

Thanks for the replies. I think I've read almost all there is about the wiring there but was really hoping I could use the feed for the ambient lighting and connect it all in the one harness before fitting it in.

I may dig out my multimeter and see what the blue and grey wires do, perhaps that's where I need to look first. I saw mention of blue with red stripe being illumination so there could be a link there with the plain blue in the mirror harness... probably too simple though!

MikkiJayne · #3 7th July 2021, 08:41 PM

Didn't we have a thread on this recently where we decided it's possible to do it with four of the six wires on the mirror, just using things that are in there already? If I recall correctly, the only things which aren't there are the reverse signal (to disable the dimming) and the output to the door mirrors (which aren't there anyway).

pete-p · #4 7th July 2021, 09:18 PM

That might have been me in the sale thread

http://forum.a8parts.co.uk/showthread.php?t=15718

I'm sure it's possible, just need to identify which of the three remaining wires to use.

steamship · #5 8th July 2021, 10:05 AM

Just to confuse you even more. I knew I'd posted about this before but couldn't remember when and couldn't find it last night. Finally found it:

http://forum.a8parts.co.uk/showthread.php?t=12806

pete-p · #6 8th July 2021, 10:16 AM

Thanks Sean. I read your post there and it was very helpful as mine has the same coloured wires as yours.

One thing I see from that and which probably ties in with what Andrew noticed, there is a feed to the dimmer from the interior lights. I wonder if this is to cancel the dimming when the interior lights come on? Could be handy to connect this one up to make it easier when dropping someone off!

HPsauce · #7 8th July 2021, 10:20 AM

Quote:

Originally Posted by pete-p

I wonder if this is to cancel the dimming when the interior lights come on?

That's the sort of clever feature that you'd expect on an '8!

Though personally I'd probably avoid using that input unless you're doing a full OEM install - you just never know how the various controllers interact so KISS.

I also note from that thread Sean took power from the sunroof (as I did on my PF) and similarly just found a good earth point.