http://www.wikihow.com/Find-a-Parasitic-Battery-Drainis
Above is a pretty good link....but you'll need a good VOM capable of reading amps and a FSM (for the wiring diagrams)...as stated in the link after connecting the amp meter , wait a few minutes for the computers to go to "sleep"..to be safe i'd say 5-7 minutes, THEN start puling fuses one by one. A amp meter is much better IMO than trying to use a test light as you see in the video. Also there are many good videos on YouTube about checking for a battery drain (current draw) If you have patience and take your time it's not that difficult for a weekend "diyer" IMO.IMO the drain is more than some accessory pulling the current. charge battery up fully and when car is cold feel the alternator. it should not be warm to the touch. they have internal regulators which can stick thus causing a major drain. had it happen to me on a car. mechanic suggested i check it and sure enough my alternator was hot when it shouldn't have been.
Allan Brenneis Nashville Tn. 1990 Polo Green Coupe Saddle Interior Chrome ZR-1 Rims https://www.c4vetteregistry.com/member_uploads/14501_14600/14572/image2014329104347r.jpg