Cadillac SRX Trailer Wiring | etrailer Best 2010 Cadillac SRX Trailer Wiring Options. Speaker 1: Today we're going to be taking a look at the best custom fit vehicle wiring options for your 2010 Cadillac SRX. To determine which wiring harness you're going to need, you're going to need to know if your SRX has the tow package or not. Cadillac SRX Trailer Wire Harness and Connector - Best Order Cadillac SRX Trailer Wire Harness and Connector online today. Free Same Day Store Pickup. Check out free battery charging and engine diagnostic testing while you are in store.