Circuit/System Verification
WARNING: This page is about a different car, the 2016 GMC Acadia, 2016 Chevrolet Traverse, and 2016 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
Supply sufficient light to simulate daylight conditions to the ambient light sensor. Ignition ON, engine running, and the gear selector in drive. The DRLs should illuminate.