Ya as others said check the plugs under the van behind the drivers seat.
A few years ago, we went into the local hospital in a driving rain storm to see the wifes mom. Power slider on drivers side decided to open back up and I saw it close. We was inside for 30 minutes to 60 minutes and came out to a wide open door and water everywhere behind the drivers seat. Van started but the fuel gauge was crazy. Went to the mechanic and he pulled the plugs under there and they just dripped water everywhere. Blew them out and dried the best we could and it was fine, went back to normal. Did find some green in there too so it had been wet before. I tired some contact cleaner and stuff on the connectors and it seemed fine, then one day it wouldn't start. Hmmm no fuel pump sounds, got under and pulled the one I knew went to the pump and sure enough more green so plugged and unplugged it a few times and all was fine. clean it all again. Now I am like months and months later I am 6 or 7 hours from home in a city where I know no one and it does it again. Daughter is freaking as she has just moved there for school. Well I know what it should be and sure enough I do the same thing and it fires right up. Get back home and clean it again but now the contacts are mostly just the steel. I then remember someone giving me so HIGH voltage HIGH current protection spray. So I spray all the plugs under there. I did also get some dielectric grease but so far its been 3 years and hasn't happened again, so I never did use the grease.