DRL-daytime running lights

[Scupper]

2000 GMC Yukon XL.

I finally got around to replacing the bulbs for the DRL's on my Yukon. The bulb sockets showed virtually no signs of corrosion and minimal signs of burn. They have not worked for over 2 years and I did not replace them earlier as it seemed that they would work for a few months and burn out when I did, so I just let it go.

The new bulbs did not illuminate. I tested the sockets with tester and found no power. Pulled the fuse and found it to be good. Replaced it with new fuse just because, and still no power at sockets. Again pulled the fuse and tested fuse block. Power on the left side of fuse receptacle which I assume is normal. I also pushed the button/switch by the dome light 4 times as instructed in manual to reset with no luck.

The low light sensor for the headlights works fine.

I have spent a few hours on the internet searching for answers and am finding myself wondering why I am spending so much time on such a little matter.

Any other ideas or thoughts as to where I should look?

Thanks for any information and time you put into your response...

[Jeremy airjer W]

Doesn't it have to be running (key in the run position) and in drive and a sunny day in order for them to turn on?

[crothmeier]

it has to be in drive in order for the lights to be on. thats the way it was with my 2000 silverado anyway. . .

[Fishinguy40]

If I recall correct my, GMC headlights always had power as long as the fuse was good. The circuit to turn them on was completed by completing the path to ground. So there should always be 12 volts at the headlamp but they won't light until the relay energizes and ties the other side of the lamp to ground.

[Scupper]

Tested with the motor running and in drive position as suggested in the owners manual. Sorry I did not enter this information above although it was the same results, no illumination.

Not to sure as to having to be a sunny day. I'll monitor...

Thank you for the replies. Any other thoughts???

[LMITOUT]

Emergency brake wasn't on was it?

[Scupper]

There On!

While sitting in traffic at a red light today the sun peered thru the clouds with it's brightness. The vehicle in front of me was a green suburban.

I noticed 2 glowing reflections in his paint. It was indeed the 2 lamps I recently installed.

Wait, there's more.

As a positive side effect to this, my once working courtesy lights have magically started working again. I gave up on them a couple years ago. They have worked manually but not automatically as they once did and for now do.

Thank you all for taking the time to respond to my post with your expert advise. It is truly appreciated by block heads as myself.

Scott