What sensor/controller should i check to replace.

Good battery, new starter, no issues prior. Next day nothing, no clicks.
Battery at 1.28v. I put in a good battery(12.56V). Interior lights and dash
lights come on. Step on the brake and lights go dim on the dash. No start,
and cannot shift into neutral. Dash lights come back on after a minute or so.
Battery positive cable is hot and battery voltage has dropped to 10 volts
after about 20 minutes of attempting to tighten cables, clean posts, shift into
neutral. After disconnecting and reconnecting power, i hear a light noise
similar to a blower motor near passanger side firewall for about 20 seconds
and then quit.