I went to do some business. The car started up fine when I went to the store, but the car wouldn't crank, it said no Fobs detected. I had the remote control battery changed out, and it still wouldn't crank. The door wouldn't unlock with the remote, and I had to use the key. When I get inside the car and back out, the Alarm sounded off. All the lights were on. I mashed on the brake, it still says the fob wasn't detected after the batter in the remote was changed.

I unhooked the battery terminals, waited 5 minutes, hooked them back up, the same thing - "NO FOB Detected". I had gotten a spark when I hooked the red power cable back up, like something was still on. I had changed several batteries in the car over a 2 years period, and they said all the battery indicated dead cell. All the batteries were new. My question is what can possibly be left on that's killing all those batteries so fast. If I let the car sit three days, it won't start even with a new battery. What possible can kill a battery that fast that can be left on? Thanks!