Rich, thanks. The light has never been on and I have not hooked up a trailer during my 4 yr ownership of the vehicle. At first, i thought it was a battery indicating light, but looking at i more closely, the image seemed more like a trailer. Icon not in the manaual, but it seemed related (after internet search) to a tow brake issue. I have to hook up my OBD Alpha, but it isn't co-perating at the moment. I am thinking now, maybe a short (rainy day) and water is dripping down from inside left of upper cab (unknown point of origin). Always, something. I will check tow wiring, double check battery, and try resetting light via OBD or battery disconnect.