As the title says, what’s the original purpose of the brown/white resistance wire that goes from the brown wire (accessory power feed) of the ignition switch, to the brown wire (alternator warning lamp wire to the regulator) at the firewall connector?

I asked this because a friend called asking about a charging system conversion on a 68 Lemans. The only thing I can think of for why it’s there is so the charge lamp glows dim in the accessory position. Was it intended as a reminder that the key is in the accessory position?

 

Nobody has a clue?

 

It acts as excitation in case the lamp burns out causing the alternator to charge.

 

^^^this!

 

That makes sense. Always wondered, now I know.