Troubleshooting Snowmobile Trailer Brakes That Lock Up When Trailer is Connected to Tow Vehicle

Question:

Hi, I have a 2009 29 foot Legend enclosed snowmobile trailer. The tow vehicle is a 2018 GMC Sierra 3500 Duramax. I have hooked up to my various boat trailers with no issue but when hooking up to the snowmobile trailer the lights come on but the brakes wont release. Just moved to a new town and dont have anyone I trust to look at it. What should I start checking? Could the ground be bad if the lights work? Could the cord connection be bad if the lights work? thanks.

asked by: Matt

Expert Reply:

If the brakes on your snowmobile trailer activate and stay locked up when you connect to your 2018 GMC Sierra 3500 then that should actually be a pretty easy fix.

The pin in the 1 o'clock position on your Sierra will carry your 12V power which should be constant power (at least with the ignition on). What I believe is going on is that the brakes on your snowmobile trailer are connected to the corresponding pin on your trailer side connector.

Try verifying this by taking a 12V battery and grounding the negative terminal while using the positive terminal to power the various pins on your trailer. If I'm right then the pin in the 11 o'clock position on your trailer side 7-Way will activate your brakes. If this is the case then you simply need to do is swap that wire out to the pin in the 7 o'clock position on your trailer side 7-Way. If you need some more wiring you can use 10 Gauge Wire # 10-1-1 and Butt Connectors # DW05745-5.

I have attached some pictures of vehicle and trailer side 7-Ways that you can use as a reference. If you find that everything is actually wired correctly then let me know and I can help you troubleshoot further.

expert reply by: Jon G