Daytime running lights not working and headlights burn all of the time

No. It works properly as indicated by it's affect on the dash lights. I suspect a relay or some type of switch. I bought this truck new and know my way around her fairly well, but I am not much of an electrician.

When these "headlights" are on and you use the dimmer switch... Does the high beam Indicator work..on high beam?? If you can let me know that I have an idea... Also how do you get the lights to finally turn off??

Yes, the high beam indicator illuminates. All functions are normal execpt for dtrl not burning and headlights burning anytime the ignition switch is on. I have replaced bulbs, stalk switch and dashboard headlight switch. The headlights only gp off when ignition is off.

Next test.... Start the engine.. Push the dome light override button in and let it out 4 times and see if lights turn off after an audible tone... Post results..

two cycles of "in and out" resulted in headlights off. Two more resulted in them back on. Dtrl's still not functioning. So yes, I think you are on the right trail!

There has got to be a problem with the twilight sensor on the dash... Take a really good flashlight and shine the beam on the sensor for about 3 minutes (or less) and see if the lights turn off...engine running...BTW... Are tail lights on as well?...Post those results...

Will do, but I am curious, by manipulating the dome light over ride were you testing the relay circuits? Tail lights, brake lights, back up lights, side markers,..etc. all function properly. The dtrl's not burning and the head llights burning continuously are the only abnormalities.

Just look and see if the tail lights are on with the engine running, don't move any switches.... Then test the twilight sensor on dash with flashlight...Post those results for now...Will explain why later!!

With auto headlight function overridden, the tail lights are not illuminated. In normal auto headlight mode, they are. Light on the twilight senson has no effect on any lights except the dashboard as it should. ?????????

It is no longer a DIY diagnosis nor one that can be 'reasonably' accomplished over the Internet.... A professional scanner is needed to check the BCM to find out what it's live data reads... The headlight circuit must be receiving input from the DRL circuit... Scanner will show what mode the BCM is commanding... Good luck with it!

Thank You for trying!

Sure