Modern cars including Morgan trads built 2014 on have a BCU (body control unit) to handle electronics attributable to all functions outside the basic running of the engine, timers, switch latching, logic inhibits for light operation etc. Because there is a spill over between these functions there is a CANBUS interface between ECU and BCU.
Earlier cars have variants of the awfully fragile and exposed PCB as an early form of BCU. This allows the possibility to replace with basic relay control as Rog has done, although I believe without any timers. I think I'm right in saying the logic required within the PCB to provide the momentary switch latching is lost in such case hence need to replace with simple toggle switches. Perhaps Rog could confirm but if so it appears that Borghi offers similar as his version appears to employ retro toggle switches as well.
Rog has confirmed there is a CANBUS interface from ECU via an MFU to control ignition warning light, tacho etc. on earlier models but it seems minimal compared with later cars.
