2013 Duramax

[outbackmac]

i have a 2013 chevy duramax today when i hooked up 5th wheel i was getting a warning on my dash, ( service trailer brake system) what could cause this? I was thinking maybe a bad connection at my 7 way pins connector?

[Old-Biscuit]

Most Likely...^^^

Clean up the 7 pin receptacle on truck and the 7 pin plug end on trailer cord

Check that they fit together TIGHT and plug stays inside the receptacle

[xc-mark]

poor connection at the 7 way round is the most common cause. If you have electric over hydrolic disk you could have a issue with needing a CAM if the trailer is new to you. last possible cause is the trailer brakes may have a wire shorting to ground , often inside the axle the OEM run the wire thru drilled holes and its unsupported inside the axle tube.

[Newmar2856]

I had a similar issue on my 2016 back in the day. It was the ground wire in the pin box. It had wiggled loose after bouncing around on our lovely highways. A new wire nut and some tape resolved the issue.

[Tightwadted]

Another possibility is the trailer brake module on your truck, on my 2015 itis under the bed, above the spare tire mount, had to replace mine, it would even show fault when trailer not connected. Youtube it to find exact procedure for replacing yours.

[Wileykid]

I had a 2016 Chevy 2500, and the same problem, turned out it was the trailer plug on the truck. It was filled with water, and had corrosion. Fixed under warranty.