I found on mine that there is a connector on it's way to the plug that has a high resistance through it. I actually has almost a volt difference between each side. I need to replace it but just haven't yet. Probably not your thing but it's easy to get to after you remove the front storage tray and just follow the leads back from the plug to near the driver's side. That resistance just tells me that it could fail sometime and as it just goes to that fuse, it's possible yours has.