I had posted the question about how to repair my drl's, and got lots of good answers, but everyone missed one problem, which turns out to be quite common. After the obvious most common issue of bulb replacement, the second most common cause is socket burnout. Hopefully, this will help some of you get your DRL's going again. Before doing anything, check the drl's for operation: 1. Block your wheels so they cannot move with the engine on and vehicle in gear. Do not use the parking brake, as that turns off the drl's; 2. Start the engine, place vehicle in gear, remove your foot from the brake, and determine without a doubt that your vehicle will not start moving; 3. Check your drl's for operation. Now that you know they are not working, get two new bulbs. Locate the drl socket behind the lower part of the grill. There is a release tab on the side of the socket (see pic). Squeeze that tab as you turn the socket to the left, or down. It is a bear to get them to release, but that is the only way to do so. With the socket out, remove the bulb, noting the orientation of the contacts on the bulb to the socket. Replace the bulb, and repeat the above checking procedure. If the bulb lights, you are obviously good to go. If not pull the bulb, and check the socket for darkened, brownish burn areas (see pic). If the socket has the burn areas, it needs replaced (both of mine did). I got my sockets on amazon, for about $12.50 each. They were also available on a GM parts site for $30 each. Both were original AC Delco #15306157, correct for my 2001 Silverado 1500. They come with two crimp connectors, and about 2 feet of extra wire, which I did not cut down, but doubled back and and taped off in case I need to do another repair. You MUST cut and repair one wire at a time, in the proper orientation to the original socket wiring. When you have completed a socket repair, insert a new bulb, being sure the orientation is correct. Set the socket somewhere you can see from the interior (see pic), and start the vehicle and put it in gear (again, no parking brake) to be sure it lights. To reinstall the socket, coat the three small tabs with a bit of PJ to reduce friction. Insert the socket into the fitting, with proper tab orientation, and rotate to the right, or up. It can be a b***h getting them in, but they will click in place with a little work. I used yellow bulbs because they are more visible in all weather conditions. I do not know if they burn hotter, which could reduce bulb or socket life, though I did use them on a 2000 Silverado I had years ago, and they lasted two years, at which time I sold the truck. Good luck with the repair.