How do you turn off automatic light on a 1999 Chevy silverado?

There's no single "automatic lights" switch in a 1999 Chevy Silverado like you might find in newer vehicles. The automatic headlight feature (if equipped) is integrated with the dimmer switch. To disable automatic headlights, you'll need to manipulate the headlight switch itself.

Here's how to likely turn them off:

* Check your dimmer switch: The dimmer switch itself likely has positions for "Off," "Parking Lights," "Headlights," and possibly other settings. Make sure the switch is firmly in the "Off" position. If there is a separate "Auto" setting, switch it to "Off" or another position (Headlights or Parking Lights).

* Look for an "Auto" indicator: Some 1999 Silverados might have a small indicator light on the dimmer switch or instrument panel that illuminates when the automatic headlights are activated. If you see such a light, switching the headlight switch to a different position (likely Headlights or Parking Lights) should disable the automatic function.

If you've tried the above and the headlights still seem to be turning on automatically (perhaps with the ignition), there may be a fault in the system. The light sensor might be malfunctioning, or there could be a wiring issue. It would be best to consult your owner's manual (if you have it) or take your truck to a qualified mechanic for diagnosis.