Windshield Wiper/washer Switch problems of the 1998 Plymouth Grand Voyager

Intermittent wiper function ceased working correctly. Would wipe a couple times then quit. Turning it on and off caused it to work a couple more times then quit. Dangerous, since one relies on the intermittent function to continue to work. Problem came and went. More noticeable in wet weather (when of course you actually need the wipers) then in the dealers dry shop. Finally dealer replaced the multi-function switch. Worked better for a while, then same problem returned. Dealer cannot find anything else wrong. Refused to consider clock-spring problem.