1998 GMC Sonoma Owner's Manual - Page 105

The DRL system will make your headlamps come on at reduced brightness when: e the ignition is on, Fog Lamps (If Equipped) Use your fog lamps for better vision in foggy or misty conditions. Your parking lamps or low-beam headlamps must be on for your fog lamps to work. The fog lamp switch is on the instrument panel under the lamps switch. Press the switch to turn the fog lamps on. Press the switch again to turn them off. A light will glow in the switch when the fog lamps are on. Remember, fog lamps alone will not give off as much light as your headlamps. Never use your fog lamps in the dark without turning on your headlamps. The fog lamps will go off whenever your high-beam headlamps come on. When the high-beam headlamps go off, the fog lamps will come on again. the headlamp switch is i n automatic headlamp mode and e the parking brake is released. When the DRL are on, only your headlamps will be on. The taillamps, sidemarker and other lamps won't be on. The instrument panel won't be lit up either. When it begins to get dark, the headlamps will automatically switch from DRL to the regular headlamps. When you turn the headlamp switch off, the regular lamps will go off, and your headlamps will change to the reduced brightness of DRL provided it is not dark outside. To idle your vehicle with the DRL off, set the parking brake. The DRL will stay off until you release the parking brake. As with any vehicle, you should turn on the regular headlamp system when you need it. Interior Lamps Brightness Control Turn the switch next to the headlamp switch up to make your instrument panel lights brighter. Turn the switch all the way up to turn on the interior lamps. 2-41