This harness is for OEM ZL1's, not for those who did a ZL1 front end conversion. If you did the front end conversion, this is the harness you'll need: ZL1 Fog Light Harness . This harness makes it so that your DRLs will be on whenever your ZL1 headlamps are on.
Step 1- Turn the wheels all the way to left to gain access to the screws on the passenger side fender well liner
Step 2- Remove the 3 (T20) torx screws holding the fender liner to the bumper. ZL1 owners also remove the 3 screws under the bumper. This will allow you access to the forward lamp harness connector.
Step 3- Locate the forward lamp harness and disconnect.
Step 4- Plug our harness inline
Step 5- Reconnect the other end of the harness to our harness.
Step 6- Verify operation. With headlamps on your DRL's should also be on.
Step 7- Reinstall fender liner screws.