1991 Toyota Other battery draining & electrical short;

Hi my battery slowly draining when parked for a few days-week, has new alternator, battery ok, I found white thick wire that connects to battery gets very hot/little smoke when ignition on, I think starter/ignition wire won't start with out it and only wire that lights up the dash lights, does not get hot or even warm when motor is running, not blowing fuses, (I think battery draining and hot wire are different issues, I'm not sure) vehicle is 91 Toyota surf import 2:4 turbo diesel, Any help/Advice would be appreciated, cheers!. This is my first time question, I will be happy to make a donation next time I ask a question, please when you e-mail let me know what a suitable amount would be !