Toubleshooting Trailer Not Connected Check Trailer Wiring Error on 2019 Silverado 3500

Updated 05/20/2024 | Published 05/04/2024

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Question:

Hi - I have a 2019 Silverado 3500HD with factory integrated trailer brake controller. Experienced loss of trailer brakes on my 5th wheel, ended up changing to electric over hydraulic with hydrastar brake actuator. I did not install a separate break-away battery kit. Worked great for about 500 miles, now getting alternating messages trailer connected with check trailer wiring - which unfortunately disables the trailer brakes. I cant seem to find the problem. Thinking of installing a Prodigy P3® Proportional Brake Controller - do you think this would fix the issue? would I still get all the dash messages?

asked by: Bill M

Expert Reply:

Are you getting any errors related to the brakes? It looks like the 2019 Silverado 3500 detects the trailer through the running light circuit so it may not be brake related. I would start by double checking the vehicle and trailer connectors for damage or corrosions. I would also check all of your ground connections and make sure there is no damaged wiring on the trailer.

If it also gives you brake related errors it could be brakes themselves or the brake controller. The P3 # 90195 can be installed using the # 3016 so that wouldn't cause any errors plugged into the factory wiring. Before you add a new brake controller I would double check the one you have now. You can test for power with a circuit tester like # PTW2993 and also check the other wires right behind the brake controller. If this checks out I would double check the power and ground running to the brakes themselves on the trailer.

expert reply by: Robin H

Bill M.

5/20/2024

Hi Robin. I have checked the trailer wiring, cannot find a problem. I have no brake errors, only the check trailer wiring / trailer connected messages. On the last leg of our trip, I did not engage the tow/haul mode and everything worked fine, no error messages for ~200 miles and brakes worked fine. I then engaged the tow/haul mode and within about 5 miles started getting the same errors and loss of trailer brakes. I pulled over, turned the tow/haul mode off, turned the engine off for a few minutes. When I restarted the engine, the error message came back within a minute. At this point, I am inclined to change the brake controller to one without the built-in-test function. Would like your recommendations

Robin H.

5/20/2024

@BillM the # 90195 listed above is a great option that is really popular so that is one way to go. However, my personal favorite is the Redarc Tow-Pro Liberty # RED24FR. The main unit installs behind the dash so only the knob is visible much like an OEM brake controller. This keeps it from taking up space and gives it a nice clean look. You can use the same Tekonsha # 3016 wiring harness along with the # 331-TPH-017 for a plug and play installation.