If you plan on fording water, make sure all your drain plug under your carpet are in. I had a courtesy light that wouldn’t come on and it caused problems (locked me out of my car with my kids inside...happened to my wife too). I went digging last night to see if I could track it down. I replaced the switch in the door but that was no good, so I traced the wire back in the door sills and noticed that there was a lot of red sand in the sills...and an empty hole. OOOPS! I found the culprit at a junction where the rear wire met the front and the supply and it was corroded to hell. replaced and working. I also plugged the hole. probably has something to do with the above picture.