Battery drain problem

You need to do a parasitic drain test , There's a few ways to do it You'll have to learn on line it can't be explained here . ,Try disconnecting fuses maybe you'll get lucky and find the circuit the problem is on . I guess you could pull fuses in the dark and look for an electrical arc . Don't put too much money into an 8 year old P.O.S. car like that .

First thing I always do when trying to find a draw is electrically disconnect the alternator and recheck for draw, 8 out of 10 times it is that. The diodes start to bad and allow power to feedback into the alternator killing the battery.