Three problems related to windshield wiper/washer have been reported for the 1999 GMC Sierra. The most recently reported issues are listed below.
The windshield wiper would intermittently stop during operation.
While driving on an interstate highway at 60 mph in a heavy rainstorm the nut that holds the passenger side windshield wiper arm onto the drive shaft backed off and the wiper arm contacted the driver side wiper arm and stopped both wipers from opperating.
I am not sure if this is the correct forum for voicing these concerns but I hope and can be enlightened about these problems. I am not sure of the exact mileage or dates of any of these incidents without further study. The seatbelts on this truck will lock up intermittently while driving down the street with no braking. The right windshield wiper has broken free from the mechanism twice. The daytime lighting does not work though the lamps and fuses are in working condtion. The power steering pump sheared a shaft in two and was replaced under warranty. The engine clatters and was fixed once by the dealer however the fix has never lasted more than half of an oil change(1,500 miles. ) the headlight and rotary dimmer switches and surrounding trim on the dash get extreemely hot to the point of burning. I know I have missed something, it's hard to believe that so many things have gone wrong with this truck.