I heard a buzzing noise coming from under my 2013 4Runner that had been idle in my garage, keys removed, for a couple of hours. It seemed to be coming from behind the spare tire and as I felt around (blindly!) and followed a wire to it's harness, the buzzing stopped. Dropped tire and found a small module (about the size of a pack of cards) mounted on the driver's side, forward of the spare tire center and somewhat close to the shock / spring (left, in picture). Any idea what it's for? Could it potentially vibrate if the wiring harness was loose? There's a much larger module in a plastic case (center, in picture); could be that one, too. For perspective, you can see the chain used to lower the spare tire, to the right / rear in the picture and the spare tire at the bottom.
1,004.2 KB Views: 90