Thanks for the suggestions. The mechanics at the dealer did test for drainage the morning I brought it in and found a drain of… 2 amps (I think)? I’m not very familiar with amps and mili amps but he said that was high and would definitely cause drain over a night or 2 with the vehicle sitting. Their suggestions was to power everything down so they could hunt for the drain source by checking the fuse panel. Evidently, by then, the drain stopped (weird). So I left it there overnight so it could sit for a good amount of time and they could try again with a cold start in the morning. At that point all they had done was as I mentioned above- cleaning wires and the bit of corrosion they found. Yesterday morning when they fired it up, they detected no drain. I have my car back now and it started it up this morning- still sounded slightly sluggish to me, but it was 30 degrees this morning also. In addition, now my radio doesn’t work. Clock works but I can’t tune in any stations. I remember them saying one of the things they were cleaning up was the radio and that might have been where the corrosion was, so I have to take it back at any rate to at least get my radio back. Hopefully the draining issue is resolved, but for me, things are never that easy haha.