2009 XC70 Trailer Wiring Harness

[spellow]

Hi guys, so I've been reading and I'm confused about the trailer wiring harness for my car. I'm not sure exactly what I need to buy, do I just need the harness that plugs into the plug in the back of the car or do I need other modules as well?

volvo parts site says I need this:

trailer hitch, cable harness, and control module

http://accessories.volvocars.com/AccessoriesWeb/Accessories.mvc/en-US/US/XC70(08-)/2009/3.2%20AWD/Automatic/L.H.D/ShowDocument/VCC-451668

anybody else install a wiring harness that can help me out?

Scott

[slayer8870]

Hi guys, so I've been reading and I'm confused about the trailer wiring harness for my car. I'm not sure exactly what I need to buy, do I just need the harness that plugs into the plug in the back of the car or do I need other modules as well?

volvo parts site says I need this:

trailer hitch, cable harness, and control module

http://accessories.volvocars.com/AccessoriesWeb/Accessories.mvc/en-US/US/XC70(08-)/2009/3.2%20AWD/Automatic/L.H.D/ShowDocument/VCC-451668

anybody else install a wiring harness that can help me out?

Scott

Reading in VIDA manuals it says that the trailing module (TCM) send input to the deferential electronic module (DEM), which controls the rear AWD input to the Active On-Demand Coupling. By doing this DEM ensures that less torque is sent to the rear wheel, so not to overload the AOC, or the Haldex unit so called. Also looking at the electrical diagram it seems to me that there is no way you can run only cable harness without the TCM. The latter controls the lights for the trailer as well, so I would say you need it.
Hope this helps