Windshield Wiper/washer problems of the 2000 GMC Envoy

When dealership changed oil, an oil pressure hose was found to be leaking oil from engine. Problem was repaired by the dealership. Vehicle has experienced several problems with the windshield wipers, deale has replaced the multifunction switch, rear wiper motor, front wiper terminal board and wiper module. Rear speakers have humming noises, speaker was shorting out, later consumer heard whistle noises in the rear speaker. When starting, there was a rattle noise, dealer found exhaust out of alignment. Creeking noise caused by faulty door pins and bushings, passenger side kick panel loose/falling off, dealer found right side panel loose. Alternator voltage drops with load below 35 amps, dealer replaced alternator, there was a squeak in the rear suspension, dealer found the e brake cable was chaffing on bushings, dealer repositioned e brake cable. Right front wheel bearing grinding, dealer replaced right front hub. Left front hub replaced due to growling, dealer found hub was worn.

Intermittent speed for the windshield wipers of the vehicle operates erratically. Speed for this setting will cause windshield wipers to move constantly or not at all. Dealership has examined the vehicle numerous times and cannot effectively remedy the problem. The dealership has replaced various computer chips and the windshield wiper switch.