Here is a strange one for you...
Regarding my electric mirror switch with yellow tell tale LED.
Since fitting the driver's mirror and switch, I have noticed that the yellow LED does not illuminate when I demist the rear window and mirror glass.
I ran 12 volts across the relevant wires of the switch using a trusty computer power supply unit.
The LED lit up straight away.
Put it back in the car, and again no illumination.
The wires to feed mirror demister and LED are: -
Black / White = +12 volts
Brown = Ground / Chassis
Anyone else had this situation?
Strange thing is that the mirror demister works fine but the LED doesn't light up.
I think that I may have an issue with the black / white wire that links the mirror glass to the switch LED.
I will probably need to run an extra flying lead between the mirror heating element end of the black / white and the switch end.
The circuit is as follows: -
12 volts to Fuse F9.
From the fuse to a relay hidden behind the fuse box.
The centre pin of the relay goes to the X6 floor connector in the UK passenger side floor connector.
From X6 to the door connectors.
From the door connector to the mirror glass demister element + terminal
From the element + terminal to the driver's door mounted switch LED
From the LED to ground.
The demister element and the LED have separate ground wires.
A further point - I stripped my mirror switch, because the mirror was not consistently moving when I used the rocker control.
Opening up the switch revealed large amounts of sticky green verdigris (copper oxide).
A liberal spraying of brake cleaner spray and some rubbing and scraping clean with some cotton buds and a sharp taper tipped knife, soon had the terminals all cleaned up.
On completion of the clean up, the mirror glass now moves predictably and consistantly as it should.
Here is the full cleaning procedure as written by me in Alan's mirror switch thread.
It is a bugger to separate - you need a very thin flat lever to slip the casing off the little wedge shaped tangs.
Once opened, there are three little V shaped caps (like the stereotypical hat worn by Chinese ladies in the rice fields).
These caps sit on the tips of three finger-like projections built into the bottom of the round motor direction switch. Be careful that you do not drop and lose the little caps..
I was able to polish these clean with a cotton bud soaked in brake cleaner.
There is also a strange pair of rounded brass dumbbell type things under the mirror selection rocker switch.
A good polish with the soaked cotton bud cleans them up nicely.
The contact plates underneath usually only require a little rub with the cotton bud.
I spent ages looking for springs that I thought I had lost from the mirror selector switch.. but it appears that there were no springs in there to start with. - well I think so anyway, as it worked fine after reassembly without any springs.
The real problem area is the "box-like" contacts in the switch that the V shaped caps sit inside.
These get as manky as hell and fill with copper oxide and crud.
It is therefore a matter of cleaning up all the green sludgy verdigris that builds up on the copper contacts.
A good spray of contact cleaner, brake cleaner or even carb cleaner will help wash the crud away.
I also use a thin jewellers screwdriver or a taper tipped kitchen knife to scrape away stubborn bits and scrape the metal contacts clean and shiny.
Another quick spray clean and then mop / polish up with a cotton bud.
That will cure most faulty electric mirror switches.
Worked a treat on mine - awesome!!