Troubleshooting Turn Signal Staying On After Installing Trailer Brake Controller In Ford Van

Updated 06/01/2021 | Published 05/29/2021

Products Featured in This Question

Ford Replacement OEM Tow Package Wiring Harness, 7-Way (Super Duty)

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10 Gauge Wire - Blue Primary - Per Foot

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Deka Heat Shrink Butt Connector - 12-10 Gauge - Nylon Insulation - Yellow - Qty 5

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Hook Probe Circuit Tester

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Quick Splices - Self-Stripping Connector - Closed Port - 14-16-18/10-12 Gauge - Brown - Qty 1

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Question:

I copied and pasted this post because I am having the exact same problem with my harness is it possible we have the wrong setup or part? Turn Signal Stays On All the Time When Connected Question: I am wiring a brake control in. I have the exact setup in this writeup: https://www.etrailer.com/faq-Ford-Full-Size-Van-Brake-Controller.aspx I have the fully functioning 7 pin at the back now, installed as per the above link. Everything works great on the 7 pin. Now I installed a Reese Brake-Evn controller with the correct plug n play harness under the dash. As soon as I plug in the brake controller to the harness, the right turn signal lights up solid on the dashand outside lights. It turns on with, or without the key in the on position. The turn signal lever does not over ride it. Nothing lights up on the controller. I already tried a second controller to see if the controller was defective. What is wrong and what do I need to do to fix it??? I need to tow a trailer ASAP!

asked by: Ian

Expert Reply:

I actually found another question on this same issue, and the gentleman found out that there is actually two connectors underneath your dash that the brake controller harness will plug into.

I recommend double checking that your harness is plugged in to the lower connector, or in this case, plug it in to the other connector.

If you cannot find the other connector then I would hardwire the controller instead, as while it is possible that the harness is not correct there should not be any circuits to the turn signals as that does not affect a trailer brake controller.

First cut the red wire roughly 6" from the back of the controller. If the turn signal goes out, use a circuit tester # PTW2993 to find the cold side of the stop light switch that only has power when the brake pedal is pressed and connect it using a quick splice # SWC501925-1.

If cutting the red wire did not fix the turn signal issues then cut the blue wire from the controller the same distance back. If this fixes the turn signal that means the blue wire on your vehicle was connected to the incorrect function. Tracing the wire coming out of the 5 o'clock pin on the connector will allow you to find the correct wire that should be run to the blue wire on the connector. Using # 10-1-1 you will need to splice into that wire, and then connect it to the blue wire on the controller that you cut off using heat shrink butt connectors # DW05745-5.

If all else fails, just run a new wire from the 5 o'clock pin on the connector to the trailer brake controllers blue wire to bypass the factory wiring.

I included a link to a helpful article on wiring for you to take a look at.