Trailer detected/ brake fault

[BHealy]

Been getting this error popping up stating "trailer brake fault" a long with "trailer detected". Dealership replaced the tow module saying it was corroded. But that didn't work.

Accessory mode has the low battery voltage warning. They want to blame my ditch lights that are connected to the aux switches.

Has anyone had battery issues after installing aftermarket lights? They have been on for 2 years with no issues.

Sponsored

 

[BroncoDave24]

Your tow module was corroded? Are those not inside the vehicle? One in the driver's side cargo area and one behind the passenger dash (usually). I wonder how it got corroded? anyway, the wiring probably is compromised in some way. Check the connectors where the corroded module was found.

 

[BHealy]

They've had it now for almost a week and havent found anything. Now I'm getting worried.

 

[B22-2023]

They want to blame my ditch lights that are connected to the aux switches.

This reason sounds a bit rich. But it’s easy for them or you to pull the Aux switch fuse and remove the ditch lights from the equation as a test.

Has anyone had battery issues after installing aftermarket lights?

Aftermarket lights being added (correctly) don’t cause battery issues. Ford’s entire design intent with the Aux light switches and circuitry is to have you add aftermarket lights etc.

 

[BHealy]

They also discovered that sometimes all 3 brake lights won't turn off. They are contacting fords hotline thinking it's a bad Body Control Module. At this point they have no idea.

 

[BroncoChallenger]

I was going to suggest possibly a battery failing, since your Bronc is at least 2 years old, and newer vehicles 1. don't seem to be able to keep a battery longer than 3 years thanks to all the electronics and 2. it has been well documented on here that our Broncs do WEIRD things when the battery gets low/old.

 

[BroncoDave24]

And I would want to see that corroded Tow Module.

 

[BHealy]

So it turns out it wasn't the module they replaced, but "pigtail" connection at the hitch originally that they said was corroded. They then replaced the TCM but the brake lights stay on still. They replaced the brake switch but that didn't work. They refuse to drive it because the brake lights can stay on making it dangerous, so they don't know if the Trailer detected problem has been fixed with the new TCM. They contacted the engineers at Ford to get permission to replace the BCM as their next step. Part comes in on Tuesday.

Sponsored