Trailer not registered as connected

Check your wiring to the brakes.

Definitely a wiring problem. I just saw this recently when I 'accidentally' pulled my 7 way cable loose from the trailer. When trying to reconnect the wires, I got the turn signals and brake lights working but couldn't get the connection display or actual brakes to work. The problem was one of the white wires being connected improperly. Sounds like you may have a pair that got disconnected in the junction box at the trailer.

You have a wiring problem somewhere in you brake wiring. Try plugging into a different trailer with brakes and see if trailer connected shows up on your dash again. You will then know that the problem is somewhere on your trailer.

Trailer break wire check each wheel, not unusual.

checked all the wiring - could this be an issue with the TBC?

I just went through this with my F250. Turned out it was a bare brake wire INSIDE the trailer axle. I pulled the wires out and ran new ones in tygon tubing on the outside of the axles. No more issues.

Teamfour wrote:
I just went through this with my F250. Turned out it was a bare brake wire INSIDE the trailer axle. I pulled the wires out and ran new ones in tygon tubing on the outside of the axles. No more issues.

This is a very common problem. Your trailer brake wires are most likely daisy chained so if one has a problem it can take out all 4 brakes. Definitely check for wiring issues, especially a short to ground on the +12V wire.

On an outside chance, are you turning off the truck when you connect the trailer 7-way plug? I'm not sure about Ford, but on some trucks you have to do this or the trailer won't register properly. My friend's 2010 GMC 3500 does goofy stuff if you connect the trailer with the truck running. I've also had odd behavior in my RAM if I connect while the engine is running.

KJ

LIKE2BUILD wrote:

Teamfour wrote:
I just went through this with my F250. Turned out it was a bare brake wire INSIDE the trailer axle. I pulled the wires out and ran new ones in tygon tubing on the outside of the axles. No more issues.

This is a very common problem. Your trailer brake wires are most likely daisy chained so if one has a problem it can take out all 4 brakes. Definitely check for wiring issues, especially a short to ground on the +12V wire.

On an outside chance, are you turning off the truck when you connect the trailer 7-way plug? I'm not sure about Ford, but on some trucks you have to do this or the trailer won't register properly. My friend's 2010 GMC 3500 does goofy stuff if you connect the trailer with the truck running. I've also had odd behavior in my RAM if I connect while the engine is running.

KJ

A short to ground on the +12 volt would or should blow a fuse.

Before you spend to much time on searching, make sure the connections in the receptacle and on the plug are clean and give it a good wiggle when its plugged in. Let us know when you solve it.

found issue - broken wire inside a connector near rear tire - thanks for all the help