Battery draw issue

I've been having an issue with my truck batteries for about 10 months or so. If I don't drive my truck for 3-4 days, my batteries are dead. I put new batteries in her April of last year, Interstate brand. Also put a Kenwood stereo plug and play harness, all controls and the Banks Powerbrake. I've charged batteries and unplugged the Banks unit, still drained, the charged and removed stereo and all plug and play gear, still drains. Removed the batteries, charged and let sit on the bench, they are at 12.6 volts and 12.9 volts. Any ideas? Cable continunity check?



06 GMC DMAX/AUTO 4X4, other then listed, all is stock.

Battery draw issue