1998 GMC Sonoma Owner's Manual - Page 103

Exterior Lamps 'A' I - Rotate the knob to the right to the parking lamps symbol to manually turn on: 0 Parking Lamps Sidemarker Lamps Taillamps License Plate Lamps Instrument Panel Lights \ / Rotate the knob to the right to the master lamps symbol to turn on all the lamps listed as well as the headlamps. Rotate the knob all the way to the left to turn off your lamps and put the system in auto headlamp mode. Your parking lamp and headlamp switch is on the driver's side of your instrument panel. 2-39