I agree with Martyn Culling's way as I have done this method on my +8 and lately on my S4 Aero.
Andy, does your S4 Aero have a Canbus system?
My Plus 8 has an indicator sounder that works, sometimes. I want to make something much louder, but am concerned that adding anything to the system will cause the canbus system to have a problem.
Also, do you know where the indicator relay is? I can't find it in the massive electronics box, if it is there it isn't obvious.
