Does Trailer Hitch and Wiring Communicate With the Engine and Transmission on Volvo XC 90

Updated 09/25/2009 | Published 09/24/2009

Products Featured in This Question

Curt Powered Tail Light Converter w/ 4-Way Flat Trailer Connector and Install Kit

(141)

$164.32

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(157)

$59.31

Curt Ball Mount for 2" Hitches - 3/4" Rise, 2" Drop - 8-1/4" Long - 7,500 lbs

(3838)

$30.92

Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires

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Question:

We are looking to install a 3500# trailer hitch Class III on our 2007 Volvo XC90 and have been told that these vehicles need to have a Volvo factory supplied trailer hitch and wiring due the need for a special Volvo module that not only does what your product does but communicates with the engine and transmission to change shift points and engine torque curves. We also would like to have an electric brake controller but have been told that Volvos can not have them due to not having appropriate wiring accomodations up front under the dash. If you could answer these, it sure would make things a whole lot less stressful.

asked by: Leo M

Expert Reply:

Your Volvo XC90 will require the T-One Vehicle Wiring Harness with 4 Pole Trailer Connector, item # 118411. This wiring harness will protect your vehicle's sensitive wiring and computers from electrical shorts and mis-wired trailers.

There is no wiring harness for trailer towing that communicates with the vehicle engine or transmission. The trailer wiring cannot communicate trailer weight or any other information to the vehicle. Your vehicle powertrain control module (PCM computer) senses that a change needs to be made, to shift point or engine torque curve, based on the amount of stress and fuel demand the vehicle is experiencing at any given time.

You can install a Brake controller on your vehicle but it will need to be hard wired. We have all the components needed for the installation in our Brake Controller 7 and 4 Way Installation Kit, item # ETBC7. This kit will use the 4-Way connector mentioned earlier and you will need to run the additional wiring needed for your trailer. Along with this kit you will need a brake controller and I would recommend the Tekonsha Prodigy, item # 90185, which is our best selling brake controller.

We have several hitches available for your vehicle (see link) and I recommend the etrailer Class III Trailer Hitch, item # e45KR, for your vehicle. This hitch is easily installed with no drilling required. Curt, item # C45010, is recommended for your vehicle, with this hitch, and you will also need a properly sized hitch ball (see link).

expert reply by: Robert G