You can find this product under Mercedes Benz GLK OEM Fit LED Daytime Running Lamps (70-753).
1/4 and 1/2 drives with an extension for each
Proper sized socket for wheel studs
Flathead screw driver
Philips heads screw driver
Needle nose pliers
Step 1: Remove the front wheels and the fender liner that is held in with push pin plastic rivets. Use a flat head and pry the center out with pliers.
Remove the 8mm bolts that hold the undercarriage cover under the front. The front section is made of plastic and the rear section is made of metal. If you wish, you can leave the two rear bolts in the metal portion and let the cover hang.
Continue removing the fender liner by removing the 10mm nuts located inside the fender. When you remove the nuts, the liner hangs on the exposed studs. Remove the liner.
Step 2: Disconnect the fog lights from the harness. You can remove the fog light assembly as well.
There is a bolt located on the brace near the fog light assembly with the head facing towards the rear of the car that connects the bumper to the frame. Remove the bolt on each side.
Underneath the center front, there is a wire that leads to a sensor in front of the radiator. Unplug the sensor.
Step 3: Pop the hood and remove the plastic/rubber shroud above each headlight. There are two pieces of plastic that you will do a 1/4 twist and pull as well as a tab that needs to be depressed.
There is also a center plastic piece that is almost over the radiator that needs to be removed. Use a flathead screw driver and disconnect both air intake hoses on the right and left side. Unclip the rubber hoses routed around the top.
You will now see 8 bolts: four in a line at the top and four behind the grill. Remove all 8 of the bolts.
Step 4: Remove the bumper by pulling it out and down. You can spread out a few towels to set the bumper on so it doesn't get scratched.
Step 5: Remove the black plastic fog light grills by taking off the black plastic liner attached to the bumper. There is a top and bottom liner. The bottom comes off pretty easily when you pull from one side and release each clip as you go. The top liner can be removed by popping the lower metal rivets on each side.
Step 6: Replace each black grill and put the liner back together. You can use a wrench to bang it back into place so it would snap in. Put the bumper back onto the car and make sure each side fits back in to the proper place.
Tip: You can take out the LED light assembly out of the plastic piece and put it back on once the bumper is secure.
Step 7: Once the bumper is back on, plug the resistors into the stock harness and run your left LED harness to the right side of the car. Plug left and right harness into DRL module.
Unplug the right side headlight harness and pull back the black electrical tape the expose the wires.
Connect red wire to battery +, black wire to ground, and connect the resistor decoders back to stock fog light adapters.
Plug the harness in and test your lights to make sure everything works.
Step 8: Tidy up the wires by wrapping them up in electrical tape. Zip-tie everything back into place. Mount the resistors onto metal and hide the DRL module box somewhere where it won't get water damage, like underneath the bumper frame.
Step 9: Put everything back in reverse order. Enjoy the new LED daytime running lights on your Mercedes GLK.
Thanks to Ben Conner from MBWorld for providing the photos and overview.