Join Date: Mar 2002
Location: Austin, TX, USA
I figured it out! [img]graemlins/hurray.gif[/img] Just as I thought! The bulb is connected accross the accessory power circuit and the guage power circuit. So normally the bulb sees 12 volts on both sides and is unlit.
A brown wire from the bulb connects to the firewall connector in position D-3 which passes through to a 20 guage pink wire to the gen light lead on the charging system. But also connected to D-3 on the underdash harness, is a brown-white wire connected to accessory power.
Seems like when the gen light circuit grounds the line to indicate a fault that it would fry the accessory power wire. The secret is that the accessory power wire is a resistance wire with a resistance of about 18 ohms. On my 68 harness the brown / white wire loops down toward the console connector and back up to get adequate length and resistance.
When the generator / alternator grounds the GEN line, instead of frying the accessory power wire it just gets warm to the tune of 800mA worst case. It actually should be much less than that since the bulbs resistance is less than 10 ohms and will carry a majority of the current.
I am not quite sure why the accessory wire is even there, but a have a couple of theories I won't go into.
So a CS-130 is plug and playable in an external regulator system.
[ 02-24-2004, 05:52 PM: Message edited by: dnult ]
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI