As crazy as it may sound, I took mine into the dealership and they had no idea what it could be. So, they took off interior door panel to find out what may be going on and a plug was simply unplugged. Plugged back together and everything worked fine. We bought the vehicle used, so cannot speak to it's previous life, but the fix was much simpler and much less invasive than I was afraid. Hopefully yours will be as simple as well!