I've been searching online and found info on how it works, sensor in rear of mirror (faces forward), signal from it goes to the lighting stalk switch and then to a control unit presumably behind the dash. Info has it that the input to the control unit is high, 12V or similar and the sensing circuit in the mirror simply pulls the signal down to ground.
So it seems to me the easy way to prove if it's the mirror is simply to unplug it. Sure enough with the cable disconnected the lights go out. If it hadn't it would point to either a wiring type fault or a dodgy control unit.
If I'm missing something please holler!
Now, I know the light sensor on the rear of the mirror is working, it's also used to control the mirror dimming function, and that works perfectly, so my reasoning is that something is toast on the pcb inside the mirror.
So my question is,
A) does anyone happen to have a circuit diagram of said pcb to enable fault finding?
B) if not does anyone have a scrap mirror lying around that I could scrounge the pcb from? It shouldn't be too difficult to trace the circuit out and then suss out how it works (my background is 40 years in the electronics industry). I don't want to dismantle my mirror again until I have an understanding of how it all works, I could be Jagless for a few weeks
Once I have a circuit drawn out I will put it on here for all to use etc.
Terry