Troubleshooting Curt TriFlex NEXT Showing Short Message When Manual Override is Applied

Updated 08/18/2024 | Published 08/13/2024

Question:

Hi there Just got done installing the Curt Triflex controler on my 1999 Ford F-250 Superduty Power Stroke Diesel and I am getting a short message when using the controller manually. Also no brake lights, but the trailer brakes are working. Does my Ford NOT allow a second input for trailer brake lights or do I actually have a problem. When I unplug the controller and power it back up I get a green check, trailer connection good. Brake lights do come on with the vehicle brakes, Your thoughts Thanks Randy Flint Mi.

asked by: Randy L

Expert Reply:

Hello Randy. The issue you are describing sounds like either a short on the brake wire on your 7-way, or a ground issue. The first thing to do is check the ground on your 7-way and make sure it is grounded to a good clean metal surface. Next check the 7-way on your trailer and on your vehicle. Dirty or corroded pins on the connector can cause these kinds of issues. You can try unplugging the trailer from your vehicle and see if you still get the error code. If the error code goes away, we can narrow it down to something on the trailer side. If it does not go away the issue lies on the vehicle side. The next thing to do from there is inspect the wiring on the vehicle. A short is usually caused by damaged wire so be on the lookout for any cracked, bent, frayed or otherwise damaged wire and replace as needed. With your car being over 20 years old, damaged wiring is within the realm of possibility.

expert reply by: Jesse M

Randy L.

8/18/2024

Thanks Jesse I think you may have missed the part where I said the vehicle brakes do turn on the trailer brake lights. Controller doesn't. So I'm pretty sure I can assume the wiring and connections from the brake peddle all the way back to the trailer brake lights are good. When I unplug the controller from the supplied adapter cable and check the wire going to the brake switch and apply the brakes I get 12v current ( feed back ) telling me the adapter cable is connecting to the brake switch OK. Reconnect the trailer brake controller to the adapter cable, it still shows a short and no trailer brake lights using the controller manually. BTW I cleaned all plug in connections with Deoxit even though all looked fine. I have always done all repairs and maintenance on all my vehicles for almost 50 years, but this one has me stumped since the truck brakes operate the trailer brake lights just fine. Took the truck and trailer out for a test drive and the controller worked the trailer brakes as advertised. Nice adjustments. One more thing. I did check the controller wire going to the vehicle brake switch and it is trying to send 12v current to the switch when operated manually. Go figure that out. Thanks again Jesse Randy. L