410 Wiring

[Roger Morrall]

The load on the ignition switch is bad enough, consider also the back emf that is generated when a dc motor is switched off.

Having experienced an ignition switch failure I arranged for the switch to operate a very heavy duty relay which in turn fed the fuse that "protects" the green switched circuits directly from the brown battery circuits.

I also comprehensively increased the number of fuses so that each circuit was appropriately fused - which turned out to be the devil of a job, one that would have been very much easier if I could have had the car on a lift, but that’s another story.

My failed switch was I believe an original fitment and probably of much better quality than anything you’d find today. It’s failure pattern showed up through a very intermittent apparent misfire, initially so short that one hardly noticed, but the length of the misfire extended gradually over a period of several years until finally the car would come to a stop yet mysteriously would restart after a few seconds after the switch had cooled down.