I've been having an issue for a couple of months now. My OD/Tow Haul light will come on and off automatically. Yes, it actually does engage/disengage when it does it. That being said, the ONLY time it does this is when it's wet out. I can take the truck all over town on a bright sunshining day and it won't do it. Take it to a carwash and it's doing it within minutes. I've looked for a short but haven't been able to find one. This is beginning to **** me off! It's Spring and it's always raining

Any ideas?