As BFL13 said first find out how big the draw is. What I would do is to disconnect the positive cable and set your HF multimeter to 10 amps and read the amp draw between the pos cable end and the pos terminal on the battery. Is it more than one amp? If more than 2-3 amps something is left on. Pull each 12v fuse one at a time to see which one reduces the amp draw then you will know which circuit is the problem. If your amp draw is less than an amp say .2-.5 amps and your battery goes dead quickly I would suspect a bad battery.