Battery drain

Hello and welcome to the site! Here is a guide that we have written concerning your issue: https://www.2carpros.com/articles/car-battery-dead-overnight

Also, if that does not work for you, here is a process that I have used for more advanced electrical issues.

There is a test that anyone can do for an electrical short. All you need is a multi-meter ($15.00 to $20.00 US dollars or so at AutoZone). Disconnect one of the battery cables from the battery. Touch the disconnected cable to the other cable so any residual energy in the system is grounded out. Take your multi-meter, turn it on, and set to 20 volts DC. Take one lead and connect it to the newly disconnected battery cable, and connect the other lead to the battery post that the disconnected cable came from. You should see some sort of reading. Now start unplugging fuses, one at a time, until you see a significant drop in the meters reading. You have now identified the circuit. If the car has any aftermarket electronics (like a radio, for example), then start with checking that.

This is the multi-meter that I have: http://www.sears.com/craftsman-multimeter-digital-with-8-functions-and-20/p-03482141000P?plpSellerId=Sears&prdNo=1&blockNo=1&blockType=G1

Let us know what you find and we'll go from there.