I thought it NEVER would after driving a diesel for 8 years... On a family RV trip far from home, 530pm on a Saturday after a loooooong day, fill the diesel, go to fill the DEF, realize it's in the diesel port after about 1/4 gallon. Figure it wasn't too much, should be fine... (Clearly, I have not read about DEF in diesel concerns.) I drive out of the station and immediately start sputtering, pull into parking at the truck stop and shut it down. CRAP!!!!! Fortunately I managed to find a diesel mechanic who felt bad for me, paid cash and helped drain the tank, completely flush the line from the tank to the engine, and change the filters. Hard start, but starts. Drive to campsite and sit overnight wondering if my trip is done. The truck starts up in the am with a small hiccup, but runs fine except for "water in fuel" light. I drain the traps, but there's no water. I go through one tank (towing an RV most of the way) with additive/water emulsifier and change filters. Light still on, drain traps, no water. Run another 200 gallons towing on and off with light on (check engine light comes on after a while) and periodically checking for water (never any,) used the same additive for all fill-ups, then change filters again. Set the filters out to dry and no crystals. Clear the engine light, but the water in fuel light stays on. Truck is running perfect, getting better mileage then ever, and no hiccups at all. Thought maybe they damaged the sensor and changed that, light still on. I've tried a code reader/reset and it still comes back on.

The "water in fuel light" will not go off. Am I missing something? Is there another sensor someplace? Do I need to take it in for a full system flush? Help please...

2017 Ram 3500 dually Laramie Longhorn