Toyota Repair: 99 corolla dead battery-- current draw, drl module, amp meter

Question
My 99 corolla has had electrical issues. I had the joy of the DRL module going out and finding that problem and fixing it.

Since that problem I have had to replace the battery. Car ran great for a couple months.

Question #1  Battery is going dead in a 24hr period. Can jump start and run around all day and no problems. I checked for voltage and there seems to be a draw somewhere that is intermittent. Voltage drops from 12.6 to 11.9 and inbetween for approx 15-20 seconds and then stabilizes at 12.4 to 12.5v.

I have installed a test light inbetween the ground cable on the battery to see when I started pulling fuses one by one the light would go out. I pulled every fuse and relay one by one in the car and no change to condition. I cannot seem to find any consistency on the current draw to lead me to a specific component/ circuit to test. Any help would be great. Thanks

Answer
Does it have an aftermarket alarm system? If so try removing or disabling it to see if the draw goes away. Can you connect an amp meter between the negative battery terminal and the neg battery post, set the meter to AMP and see what it reads, it should be less than .003A which is 300 mA, to get a more accurate reading switch the meter to mA and read the mA draw.