hi ed you can run ignition supply to the warning light terminal & put a 3 amp diode in the circuit so there is no feedback. As far as the regs blowing up using a resister as you have wont cause this to happen sounds like you have been unlucky with  2 regs or you have got a faulty rotor with to high field circuit which will fry regs.

hi Ed just wanted to know if you are still making the fc demister vents & if so how much & how long to get a pair .Im just starting a reno on a 59 fc & need to have a demister set up for engineer also any ideas on what type of heater i can use thanks craig 0414951930.