So, I got wondering today what the difference is between a 3-pole external voltage regulator, and a 4-pole regulator (I know; one pole!). I couldn't find anything on Google. Does anyone have any good links? Thanks, Joseph
LOTS of good information on these sites , https://en.wikipedia.org/wiki/Voltage_regulator https://en.wikipedia.org/wiki/Alternator_(automotive)#Field_regulation
On Ford regulators, the three-prong one is for cars with a dash ammeter. Four prongs, it has an idiot light.