Separate turn signals and brake lights on trailer.

[Alloy]

After seeing the side signal lights on the 40' buses we wanted to have signal lights along the side of our 35' trailer.

Using a Curt 56196 we separated the signal lights and brake lights then added signal lights above each marker light on both sides of the trailer.

Everything works great when connected to our old 1999 F250 but when connected to a 2016 F350 the signals are opposite (right truck /left trailer) and when the bake pedal is pushed the brake lights come on signals lights on both sides flash.

We just spent $400 at a Ford dealer that did not solve anything.

Any ideas on what we should try next?

 

[ottsville]

Get a plug in light tester and check both vehicles. Something is wired wrong in one.

 

[tatanka48]

run your side turn markers off the front turn/running lights on the TV

they have a 3 wire system w/ a running light, turn signal and ground wire

T

 

[Alloy]

I called Curt technical support hoping to get some suggestions. They said the lights shouldn't be changed because DOT wants the tail/signals combined.

The dealer said we are the 3rd customer with the same issue. They've been able to add a 3rd (middle) brake light but separating the signals has been an issue.

The Ford system uses PWM or some other technology to sense if the correct load is on the circuit.

We are going to disable the sensing system for the trailer and see what happens.

 

[Teardropper]

Everything works great when connected to our old 1999 F250 but

I'd be suspicious that the wiring in one of those trucks was wrong. Were both wired at the factory wired or somebody's project? A continuity checker at the plugins would tell you if something was wrong –or hook them up to a different trailer.

T