Saw a video on installing a RV break controller in a 2019 Traverse with a factory installed hitch (could not find anything on the 2020). It showed pigtails on a wiring harness under the plastic driver side door sill. I popped the sill and did not find wires. No luck looking under the dash or behind the left hand vertical plastic scuff panel in the driver’s foot well. Any suggestions, please? Thanks.