What is Proper Trailer Wiring for a 2009 Scion xB

Question:

I have 2009 Scion xB. I am going to put a hitch on it for my Kendon Motorcycle Trailer 350lbs to tow my Harley 650 pounds. I went to a local place that does sale and installation and they told me my car needs special wiring cause they have to put a modulator in and run a power wire to the batterysomething about not enough power to just hook to back car lights. Is his correct or does your wiring kit for my car have everything and easily install? The hitch looks very easy to do.

asked by: don

Expert Reply:

The Modulite that the local place was referring to is the black box you see on part # 118468. Rest assured, this is the correct part for your 2009 Scion xB. The 2009 xB has separate brake and turn bulbs, so the box combines these two signals so it can hook up to standard trailer light systems.

There is also a loose red wire lead on the box that does need to be run to the battery. This is so the trailer is powered directly from the battery instead of pulling extra power through the factory vehicle tail lights. This is done for two reasons.

First, if you were to ever have a short on the trailer, it would blow the included fuse, instead of blowing the lights or fuses on the vehicle tail light circuits, which can be costly if they are LED lights. Second, sometimes the way the wiring is designed on a vehicle does not provide enough current to feed a trailer. This is always the case with LED tail lights and as vehicle bulbs become more efficient, it is becoming the situation on some incandescent tail light systems. Trailer lights do no get the same technology that vehicles do.

With the 118498 wiring harness and a hitch like part # 12490 from Curt, you would have everything you need, other than a ball, to safely tow your motorcycle trailer. I have added a link to the hitch and instructions for both the hitch and the wiring below.

expert reply by: Patrick B