Hey, I changed alternators because my other one was not charging. Disconnected the battery did my thing and reconnected it all up. Go to start my car and it cranks, but the green light on my LT10s does not come on. Checked the fuse at the alternator and its fine, the other wire coming off the alternator, i guess the ground is a bit beat up but Its been fine so far. Not really sure what to do.

 

find the thick red wire at the ecu loom, cut it.. splice on another and this time run it to the battery where it always should have been

clearly it was previously connected at the alt.. and somehow you have left it off the b+ during the swap.. or broke the conductivity
( look for evidence of burning on the ring eye )

connecting the ecu to the alt is a huge no no.. one shops still do, despite it being pretty clear on the diagram
B+ at the alt is NOT the same as the battery .. battery DC is much smoother.. and works as a capacitor against surges in current draw and supply

the reason this is so important is the micro lacks voltage compensation... and that FC engines are marginal in the recharge system already
this is why you should be tuning with microtechs at full load with all the lights on

 

man ill go by your house tomorrow . dont make it worst please lol