Two problems related to dash wiring have been reported for the 1999 GMC Sierra. The most recently reported issues are listed below.
When I'm driving down the road at night the dashboard flashes on and off. All of the guages go nuts and the engine dies. They tell me that the computer has been soaked with water and needs to be replaced.
Fuel pump will over heat and than short out. Exhaust always rattles engine knocks cat. Converters went out digital display stopped working.