Troubleshooting for Curt Discovery Brake Controller that is Working But Trailer Disconnect Warning
Updated 11/17/2025 | Published 12/12/2024
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Question:
I installed a 9030 brake controller on my 11/09 f250 ford. It works good but the trailer disconnect warning is on .What can i do to end the message
asked by: Butch D
Expert Reply:
Hello Butch,
Here is some troubleshooting you can go over:
Verify Wiring Connections: Check the brake controller harness. Inspect the trailer plug and wiring for any corrosion, damage, or loose connections. Check your grounds (on both vehicle and trailer side), makes sure they have a good clean connection. Having a bad ground can cause all kinds of weird issues.
Test the trailer plug: You can use a multimeter like the LCD Digital Circuit Tester # PTW2992 to test the trailer plug to make sure it is getting the correct power going out. If your trailer connector on the vehicle end is bad # C55774 would be a great replacement for your 2010 Ford F-250.
One last thing, I would try to connector a different trailer. That way you can know for sure if its the vehicle side, or there could be something not working on the tailer end.
I have also included a link to an awesome help article on troubleshooting brake controllers.
Product Page this Question was Asked From
Curt Discovery NEXT Trailer Brake Controller w/ Custom Harness - Up to 4 Axles - Time Delayed
- Trailer Brake Controller
- Time Delayed Controller
- Electric
- Electric over Hydraulic
- Plug-In
- Under-Dash Box
- Under-Dash
- Up to 4 Axles
- LCD Display
- Single Trailer Only
- CURT
more information >
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Kate F.
11/17/2025
Hey Butch, did checking the wiring and grounds on your F-250 clear that trailer disconnect warning with the 9030 brake controller? It’d be great to know if testing the trailer plug or trying a different trailer helped narrow it down. Your update could make it easier for others running into the same issue.