The part number you reference is to an older Thule Big Mouth bike rack which has been discontinued, however I believe the part you're referring to and needing is the Replacement Wheel Tray for Thule Big Mouth Roof Mounted Bike Carrier # 853-5423-56, however the upright bike arm has been discontinued with the rack and is not offered for a replacement.
If your current upright is non-operational then I'd just recommend replacing the entire rack with the Thule ProRide XT Roof Bike Rack -... view full answer...
Unless the bike has a step through frame like some women's bikes have, you won't need a frame adapter for the he Sport Rider SE # HLY74FR you looked at. I took a look that the Tern GSD online, and from the photos, the bike retention hook would grab the frame well before it bottoms out. view full answer...
We have a trailer wiring harness for your 2015 Volkswagen Golf Sportwagen but The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C56391 will not work for your vehicle.
The wiring harness that we have that is confirmed for your vehicle is The ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit # 119250KIT. This kit bypasses factory wiring and involves no cutting, splicing, or plugging into the vehicle's wiring.... view full answer...