2008 Chevy Impala Daytine running lights

The GM DRL system does NOT include any rear lights.Since I think this is very importabt I would like to modify the system to imclude them. It is probably much easier to cover the sensor that senses light and then turns on all lights. I figured that the small dome at
the center dashboard just before the windshield was it, but covering it did not accomplish the desired task. Please provide info on location of the sensor or wiring changes nessary
Thanks
Marty