The headlight stay on all the time, either daytime running lights or all lights. The car has a sensor bulb in the dash. If you pull the headlight switch on and then push off, they still stay on. Trying using the emergency brake on the off they still remain on. This is only with the ignition switch on.

does it have daytime running lights that sensor could be bad or signal light switch ...signal to the opposite side light goes out to see if comes on

Basically it's a automatic feature, there is a sun sensor on top in the center of the dash, once that detects enough light and your headlights are off the computer will turn on the daytime lights. You can trick the sensor with a bright (LED) flashlight if you need to test them.. Put the light against the windshield facing the sensor with the car running and after 45-50 sec. The daytime lights will kick on.. Note the daytime bulbs are not the same bulbs used with your headlights on..

The daytime running lights should not flash when locking/unlocking the vehicle. It should be the park lights that flash. You may have changed the wrong bulbs. These lights operate from a sensor located in the center of the dash and use the suns ultra violet rays to go from daytime lights to headlights. Make sure this sensor is not obstructed/covered by anything that may be on top of the dash.

In the 1999 Chevy Silverado 1500, the headlights are not designed to be on all the time by default. They are typically controlled manually by the driver using the headlight switch, although some vehicles may have a daytime running lights (DRL) feature. If the headlights are continuously on, it could be due to a modification or wiring issue, and it's recommended to consult the vehicle's manual and seek professional assistance if needed.

Theres a sensor in the middle of the dash by the front windshield that detects sunlight and triggers the automatic headlights. The main headlights and daytime running lights might be on a different circuit, in which case they daytime running lamps would turn off at night and the main headlights would turn on, indicating the main headlights arent working and the daytime running lamps are working as intended.

I would check all the fuses related to headlights, check the bulbs and check the switch, then last the light sensor on the dash.

what happens when you turn the knob to brite/dim the dash lights?

check to see if something is blocking the daylight sensor on the dash. If it is not being blocked check to see if the relay for the automatic lights is stuck. If any of these issues are happening then the headlights would be on switching off the daytime running lights

You may have a broken or corroded wire, pull open the wire loom that protects the main lighting wire harness behind and around the drivers side headlight area under the hood. There are splices that are known to trap water in them and short out or turn green. Let me know if you need more clarification?

Just had same problem. After ruling out easy checks like parking brake switch, and park shift selector switch, It was a burned out resistor that is located inside the front left fender. Take off the front tire, remove the inner fender liner, the ceramic resistor is towards the front. It crumbled when I removed it, Could only get replacement from dealer for about $65.

did you try removing the DRL fuse to disable the daytime running lights, and double check your bulbs and fuses for the regular headlights? I'm not much of a mechanic but I'll take that fuse box before messing with anything else.