Help with Sundeck Trailering Question

[Mark Thompson]

I just purchased a 2009 210 Sundeck that came with an aluminum, 2008, dual axle, Magic Tilt trailer with surge brakes and LED lights. When I connect the wiring from the trailer to my tow vehicle (a 2007 BMW X5) the trailer lights flash continuously and the brakes do not automatically disengage when the tow vehicle is put in reverse. I have to disengage the brakes manually at the ramp in order to back up. The trailer lights do, however, brighten when the brakes are applied and also display turn signals properly.

In additiopn, BMW intermittently displays a warning that the trailer lights are out. The technician at the boat dealership thought the LED lights on the trailer might not be drawing enough power to satisfy the BMW the lights were on.

I went to the BMW dealership. They were stumped and indicated they would have to consult with their corporate service department which is unfortunately shut down until January 5th.

Has anyone experienced this type of problem before? Does it sound like the BMW or the trailer is malfunctioning?

My previous boat tailer was a single axle without brakes and the BMW towed it fine. The difference here appears to be the addition of a prong for the backup lights.

Any help or suggestions would be appreciated.

 

[hmonarch]

Here is a link to a site that has trailer harness wiring diagrams:
http://www.accessconnect.com/trailer_wiring_diagram.htm

Are you sure the trailer has an electric reverse lock out for the surge brakes? Some trailers offer that as an option, not standard equipment.

I would begin by checking the vehicle with a test light or volt meter. If the vehicle checks out, then the problem is with the trailer.

Note that the backup light / trailer brake lockout circuit connection should be position # 7 in the center of the plug.

 

[wingless]

This U-Haul LED Trailer Adapter is required on the wife's Porsche when using an LED trailer to keep the vehicle from "freaking out" about insufficient current draw. It sounds like the BMW needs one too.

 

[sdl22]

Go buy a $6.00 lamp tester at Auto Zone, and see what is really working on your vehicle??

 

[Mark Thompson]

Thanks for the advice. Sounds like that U-Haul adapter just might be the fix.

 

[edbaughman]

Had the same problem with girlfriends Touareg and the adapter worked great. Although when the trailer was not connected and i left the plug in, it made the car computer go crazy, so make sure you remove it when not in use.