So I get my new GM 100 amper into my '81 Hatch, all the wiring done super nice, new #6 power wire from alt to battery, ext. voltage regulator removed, dash light bulb and circuit checked, 12 gauge field sensor wire from the alt to the junction, everything triple-checked, works great...so I put in the fully charged battery in, turn the key and ...nothing. No power to the ignition switch. I checked it with my meter...no power. I checked all the fuses...good. I checked my wiring diagram...AHA! It shows the ignition switch power wire (large white one) directly connected to the main power wire from the alt to the battery (clearly and unambiguously).

 

I haven't seen this connection in any of the other write-ups, and I haven't seen this connection under the hood yet. I am about to go begin hunting it down starting at the battery/junction area, but I thought I would put this out there in case someone knows the exact location of this connection. I also entertained the idea that the ig. power is relayed off the original field sensor wire, but the wiring diagram does not show anything like that. Any thoughts?

FOUND IT!

 

Factory crimp about 16 inches down the alternator wire from the original junction connection. FYI.

 

I hooked it up. Got everything tidy. Turned the key and...it fired up like a new car. Voltmeter shot to 14.5 and didn't budge with headlights and wipers on. Headlights, wipers, and heater fan took it down to 14v Runs more solid than before with more power in higher rpms and up hills.