2000 max GLE bone stock- no aftermarket anything has been installed. If driven everyday, cranks and starts fine, left idle for a day, the next morning battery is dead.

I have searched on here and seen where multiple hood, door, or trunk switches being faulty may cause the car to not go into "sleep mode" resulting in higher amp draw on system, but mine appear to be working without fault. Including the truck switch, which was fault in sev prev posts. When I close it up, and lock the doors with the fob, the security light illuminates for approx 30 seconds then starts blinking at about every 2.5 seconds. From whan I understand this is correct.

Several have indicated the battery drain could still be related to the security system so my question is, can it be disabled by simply pulling the fuse in the box in the engine compartment? I'd wanted to try this and leave it sit for a day to see if in fact this ceases the amp drain but instinct tells me this would be too simple a bypass for a security system and may cause another issue- preventing starting etc?

 

Could just be a bad battery dude.

 

^^^ what he said.

A check that you can do is park the car and disconnect one of the battery cables. Then measure the battery voltage. When you come out the next morning, measure the voltage again. It should be the same as when you parked it.

Or a variation of the above. Don't bother to measure voltage. Just disconnect the cable. In the morning, connect the cable and if the car won't start, its the battery.