I've got a good battery and alternator but still going dead if sit for 12hours.

Hello, Get a test light, they are very cheap, and check every fuse and relay for power while the key is off and removed. Let me know which fuse it is, according to the diagram in the panel or owners manual. If you do not have an owners manual, there are tons of free downloads online. Let me know, and I'll see if it should have power. There are only a couple that should, and mostly in the interior. If you put your hand on the main relay, then turn the key to any position, do you feel and hear it click? It should click on with the ignition, and off with the ignition. No exceptions.