I fitted a motorcycle designed unit (similar to those on eBay) to my S1 Aero8.
I couldn't get it to work with
any of the wires from the actual indicator stalk;tried every which way using a multimeter to no avail so I suspect there is a
(partial) Canbus system in operation.
No problem I thought,I'll piggy back onto the dashboard indicator warning lights; again,no joy - they are hidden well up behind the dash and are mounted on a rail (hope one never fails....).
Like Peter, I
still can't find the relay itself (initially ,I was going to replace this with an electronic ,sounder unit which would also deal with the LED's/flash rate which replaced the bulbs)
In the end, I took a feed from each of the rear indicator light units via the boot and mounted the buzzer inside the car on the rear bulkhead.It seems a bizarre place but actually works quite well being right behind the drivers seat - particularly when the top is down.
The only other issue was that the supplied buzzer worked on the bench test but not on the car;I suspect
Jon the Chief's explanation (above) has sussed this.I replaced with a larger,Maplin sourced buzzer and all was well.
I have to say, I feel a lot more comfortable knowing that I have not forgotten to switch the indicators off when the self cancelling fails to operate (which seems to be often!!).I'm surprised at how common the problem appears to be ;I thought it was just my car;clearly TADTS.....