Headlights on whenever truck is running?

[cam.man67]

Bit of a head scratcher here. Other morning, the GMC wouldn't turn over...turns out the positive terminal was loose on the batter. Once I tightened that up, it started up fine and has been fine ever since. However, since that time, whenever the key is on, the headlights turn on. They don't shut off unless I turn the truck off. Any idea what may cause that?

[Cape Codder]

DRL Daytime running lights. Do you have a green headlamp indicator lit on the dash panel? I pulled the fuse on my 98 so they don't come on but I still get the indicator lamp. I found it annoying that I couldn't flash my headlamps to let people go without turning the lights on then using the high beam switch.

[speedygonzales]

The only GMC listed in your "inventory" the 96 was in fact DRL. If you push the emergency brake, the lights will go off. Another indication it has DRL.

Little confused by the way you worded the thread. Are you saying prior to the other day, the lights were not on when it was running. Now that you tightened the battery cable the lights are on? Or did you not notice them on until after you tightened the cable?

You can disable it but why? Wasn't it invented to help with safety?

[1badgmc]

These trucks first got Daytime Running Lamps (DRLs) for the 1996 model year. The DRLs run your lowbeam headlights at reduced power. No other running lights (parking lights, taillights, etc.) are on while the DRLs are on. I've owned two of these trucks with DRLs and in each one I pulled the fuse (Fuse #15 "DRL/FOG") before driving the truck off the lot. When you do pull the fuse, you still have the green DRL indicator light on the dash. You can also push your parking brake pedal one click to turn them off without engaging the brake, but then you have the parking brake indicator light. The DRL module us located under the steering column. Removing/unplugging that will disable them as well.

[cam.man67]

I don't think DRLs are what I'm dealing with here. This never happened before the battery thing. There's no green light on the dash. I mean, yes, it appears to be DRLs, but they've never been on before.

[speedygonzales]

Do they go out when you push the e brake?