Trailer Brakes Locked Up

[thekkfan]

What's kind of common as well is someone not familiar with the color codes between a 4 pin and 7 pin plug. They tend to apply a 4 wire color code to the 7 pin which will make your trailer lights go wonky as well.

Never trust the color codes to begin with.

Utility trailers coding and what horse trailer mfrs use are different colors. Check each wire to verify you are putting it in the correct position before hooking to the tow vehicle. An ohm meter and a battery at the tongue work great for this.

 

[zing]

First post and I need some advice.

I just bought a used trailer off of craigslist. The trailer (16x6.5) is in great shape and has electric brakes.

When I bought it, as soon as I plugged (round 7 pin connector)it into my 2019 Chevy Colorado, (with the trailer tow package and integrated trailer brake controller) I got a service trailer brake system message on my dash and the trailer brakes were locked up.

I unplugged the trailer, plugged it into the Seller痴 F-150 and everything was OK.

So I took my truck into the Chevy dealer thinking the trailer brake controller module was bad but they said there is no problem with my truck.

The Seller then brought the trailer to my house with no issue.

So my question is, where do I start trying to diagnose this problem.

I thought trailer wiring was basically the same on all vehicles, trailers, but could the trailer be wired differently?

Any advice would be much appreciated.

Thanks for reading this far!

On the bright side, you know the trailer brakes are working and aren't rusted out or anything. Just need to resolve the issue of the crossed wires.

 

[MotorCityBear]

So to anyone still following this, problem solved!

My truck was wired correctly, but the trailer was not.

The trailer brake wire was wired into the position for auxiliary power on the plug. So power was always applied to the brakes. Once I swapped the wires (trailer brakes and aux power) into the correct positions on the trailer side plug, everything worked fine.

Thanks again for the help!

 

[ovrszd]

Awesome, glad it worked out. Thanks for the update.

 

[ruffdog]

The same thing happened when I borrowed the neighbors trailer. Found out the trailer and F250 were wired differently than what is considered normal. His new F150 was OK though.