How do I disable the DRLs (daytime Running lights)?
Procedure from Dreamin and bluemalibu (pictures from dreamin-click to enlarge)
Old Procedure and wiring info is here
Are DRLs required? http://www.lightsout.org/faqs.html
Step 1 (optional): Go to www.gmpartdirect.com and order a new DRL module. Part #25721769 --$28 delivered. This way your have the original module when you sell your car, and you dont have to cut your wiring harness.
Step 2: Modify the new module. Remove front cover, using flat blade screwdriver to pry tabs out. The board (PCB) slides out.
Step 3: Cut the top row, center pin - Pin "H" - see other writeup. Cut the pin completely off - i.e. cut it right next to black plastic support.
Step 4: Push PCB back in, reattach front cover.
Step 5: To access the module you need to remove the lower plastic kick panel that is located above where the drivers feet normally are. You will need to open the drivers door, kneel in to the car and put you head in the footwell area. The panel is black and is held on by four phillips screws. Remove the four screws and the panel drops down.
Step 6: Panel lowered, unclip the wire that goes to the courtesy light in this panel, and move the panel out of the way.
Step 7: With the panel out of the way you can access the DRL module. Look up from the footwell area (yep, gotta get your head in there). Look straight up, in line with the OBD port. The module is not bolted down. Snake your hand up there and simply pull it off to unclip it.
Step 8: Bring the module down into view. The wires are long enough so it will hang down into the footwell. Unclip wiring harness, you can use your finger, a screwdriver is not required.
Step 9: Swap with the modifed module.
Step 10: Snake the module back up there, clip it on, reattach courtesy light, and reinstall the kick panel.
That's it... enjoy your new !DRL option.