Both the Automatic Headlamp System and the Daytime Running Lamps (DRL) are not working on my 2006 Tahoe. I can turn the Headlamps on manually. I have replaced the dash mounted Ambient Light Sensor. All bulbs and sockets look in new condition. I have checked the DRL Fuse and swapped the DRL Circuit Breaker with a known working one, and the Parking Brake is completely off. I need to get the DRL working to pass State Inspection. Has anyone had a similar issue? Could the Auto Headlamp Switch have failed? Any ideas will be appreciated. Thank you for any and all help with this one.