I know on my 99 you literally can't turn the headlights off. First production year stuff I guess. My friends 2001 you can do the dome over ride button 3x and they'll go off. That's at night time though. During the day they go off like they should.

 

Mine stay on 24-7 and I idle a lot in the day time so my lights and wires don't last long .... replaced the plug 3 times.

 

WELL, I replaced the Sun Load Sensor with a new one fresh out the AC Delco bag and lights still stay on, so I ordered a new switch fresh out of the AC Delco box ..... lights still stay on when the key is on and I push the dome override until my finger is numb and push the park brake in direct sunlight ....... lights still stay on when the key is on!!!

Anybody got any ideas?

 

Do the lights go off with key off? If so, It is likely in the BCM (ie Auto function). A stuck headlight switch or relay would keep the lights on all the time. The 'Auto' mode trigger goes directly from the BCM to the relay, not thru the headlight switch per the schematic I have. Sources to switch and relay are constant 12V.
You can try disconnecting the headlamp switch to see if the lights stay on. If so, confirms it is the BCM trigger to the relay keeping the lights on.
Your's is probably an early 2000 model that didn't get the update from the first year configuration like BlueTexan24 mentioned if three presses of the dome override switch doesn't cut them off.

 

Are you sure you aren't confusing the DRL with the headlight? On a lot of GM trucks, the DRL is just the high beam at a lower power.

 

100% positive the headlights stay on when the key is on, they never go off no matter how bright the sun no matter what.

What is a BCM and can I replace it ...... my PCM has already been replaced.

 

OK, Professor Google told me what that is and I have emailed a company for input.

THANKS!

 

Does anybody here know about those durn BCM''s as I have not got a response from the company that is supposed to do BCMS and has a video on youtube.

Does it need the VIN number embedded?
Can I just get one from the junkyard and 30 the 30 minute security deal and make it work?
Do I need an HP tuner, or some such?

 

You may just need an updated calibration flashed in your existing BCM from the dealer. Even if you get a new/used BCM, it will need to be dealer flashed with your truck's VIN. HP Tuners/EFI Live will not talk to the BCM. I will require a Tech2 or equivalent scanner with GM calibrations.

 

OK, Thanks .... I will see my dealer then as I am tired of replacing bulbs.
BUT, something is wrong because the lights should not stay on in daylight.