A number of months ago the taillights stopped working but the third brake light was still working fine. I took it to the dealer and they replaced the control module on the left taillight so it was working fine again, then a number of months later the same thing happened and again they replaced the same module, now it's happened a third time. The problem is not the bulbs and it's not the fuse and I doubt it is the module.

What do you guys think? A short somewhere?