So i picked up a 2001 is300 on friday, and i started it saturday and sunday no problem. On sunday we lifted up the rear to replace the parking brake shoes and took apart the passenger rear side and left it off to relace it tuesday. Sunday night i noticed the clock light by the a/c controls was still on despite the keys not being in. Today i went to start the car and the battery was completly dead. No lights or anything.i tried charging the "used" battery but it did not want to charge unless i took of the positive cable from the car.it then started charging fast. I also noticed that when i take off the negative cable and reconect it, the two abs relays click. Is this normal? Any ideas what is draining the battery? Maybe the battery itself is bad. Idk at this point.... Any help would be much appreciated.