Electric Brakes Don't Work on Trailer Towed by 2016 Chevy Silverado 3500
Updated 02/24/2026 | Published 06/16/2024
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Question:
All of a sudden when towing my 5th wheel with my 2016 3500 Silverado duelly my electric brakes on 5th wheel will not engage and getting message to check wiring. It’s a newer camper and previous trips I’ve had no issues. When I plug into other campers, electric brakes work well. When my buddy hooks his truck up to my camper, the electric brakes work just fine with his truck. At a loss here….
asked by: Pat M
Expert Reply:
You will need to find out if the issue is on your 2016 Chevy Silverado 3500, trailer, or brake controller. To test the brake controller, sever the blue wire a couple inches from the back of your controller. Then use a circuit tester to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override; if it shows power at idle then there is an issue with the controller and it will need to be replaced.
If the controller tests fine, reconnect the blue wire and move on to the truck side trailer connector. Often, corrosion or dirt may be the cause of a short in a trailer connector. Check the plug to see if there is any type of corrosion built up that may be hampering its functionality. If there is, you can replace it with # HM40975 or # C55774.
You will then wan to test the brake output pin on the 7-way socket; it should only show power with the manual override. If it shows power any other time then there is a short somewhere between the connector and the brake controller you will need to find.
If the truck side checks out then you will also want to check the trailer 7-way for corrosion and if needed replace with part # A7WCB. It could also be the wiring to the brake magnets or possibly the magnets themselves. Inspect the power wires to the magnets and look for wires that may be pinched or otherwise damaged and fix as necessary. You'll also need to make sure the ground wires are attached to bare metal surfaces and free of any paint, dirt or corrosion.
You'll want to visually inspect the magnets; if you can see the copper windings coming through the magnets will need to be replaced. To test the magnets use Multimeter # PT89ZR and follow the help article I have linked to guide you.
I have also attached some help articles for you below as well which I recommend taking a look at.
Product Page this Question was Asked From
7- and 4-Pole Trailer Connector Socket w/ Mounting Bracket - Vehicle End
- Custom Fit Vehicle Wiring
- Trailer Hitch Wiring
- Vehicle End Connector
- No Converter
- No Tow Package
- 4 Flat
- 7 Blade
- Plug Only
- Hopkins
more information >
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Brooke M.
2/17/2026
Hey, how did things go after testing the brake controller and checking the 7-way connectors on your Silverado and 5th wheel? Were you able to track down where the short or corrosion was coming from? Sharing what fixed it could really help others with similar brake issues.