There isn’t one particular part number, there are several because other wiring options are contained in that left dash harness. You need to find a truck on autotrader that has the same options as your truck, but also has the aux switches. Get the VIN of that truck, call a dealership parts department, and ask the parts guy what part number left dash harness that VIN has. Some of the options that matter for that left dash harness are whether or not you have fog lamps (if so, LED or halogen), LED headlights (if so, reflective or adaptive), remote start, and blind spot monitoring. All of these features have bearing on the dash harness part number because it contains (or doesn’t) wiring/different connectors for those options.