I'm with Driver on this one. I have had the reoccuring wiper problem when it rains, thought I had fixed it by cleaning, greasing, and sealing up the back side of the wiper motor connections. During the last big rainstorm in the east we were heading up I81 and the wipers took off, I stopped and checked the motor connector and it was still dry and greased. About the same time my control for the US Gear toad brake started sounding off. I checked the connection on the back of the coach for the braking system and the boot covering the wiring was full of water. I pulled the boot back and let the water drain and the wipers and brake alarm returned to normal. The boot was filling with water and grounding the wiring in the brake connector. I filled the boot with dielectric grease and continued the remainder of the trip without incident. Don't ask me to explain it, but I believe it has to be a grounding issue.
2003 Pace Arrow 36B, W22 Chassis
Ultrapower ECM upgrade, CAI, Wires, Koni FSD