I can't explain either but someone here or the dealer should be able to.

 

Is your trailer plug good and seated correctly?

 

The fuse and relay are not for the trailer brake controller, they are for the battery charging circuit in the 7-pin trailer wiring harness. For use if you have a rechargeable battery for the break-away brakes or for charging an interior RV battery.

The brake controller will work without the fuse and relay.

 

Here's what the owner's manual says about that message:

TRAILER DISCONNECTED: This message is displayed and
accompanied by a single chime, when a trailer connection was
determined and then a disconnection, either intentionally or
unintentionally, has been sensed during a given ignition cycle. It is also
displayed if a truck or trailer wiring fault occurs causing the trailer to
appear disconnected. This message is also displayed during manual
activation without a trailer connected.

So if you have everything hooked up properly, clean and tight connections, trailer wiring is sound,etc, then this message should not appear. Probably worth a trip to the dealer.

 

Are you activating the manual control lever while you are driving? If you have the gain properly adjusted, you shouldn't need to do that. The brake controller will match the needed braking output to the trailer, based on how you are braking the truck. Again from your owner's manual:


The sliding lever on the TBC should be used only for manual
activation of trailer brakes to assist with proper adjustment of the
GAIN. Misuse, such as application during trailer sway, could cause
instability of trailer and/or tow vehicle

 

You're right. Sorry and good catch!

 

In my case this was a result of the (trailer) brake wires themselves being broken. I'd check the wires than go into the brakes on each side to see if their on good shape. For me it turned out that both wires on one side were broken! Probably a good thing that they didn't work at all. Not sure what would have happened if they locked up on one side only.

Took me a couple hours to pull the wheels, and hubs and re-wire. Now it's 100% again.

 

i was only operating the manual slide to feel how the trailer brakes were operating and to set the gain.

 

I had the same problem on my 2010 Screw. Turned out it was a grounding issue on the trailer! Double check the trailer wiring, make sure the grounds are making good continuity!

 

I have a boat trailer with surge (hydraulic) brakes, and a utility trailer with electric brakes.

The back up warning alarm comes on with the boat trailer hooked up, it does not with the utility trailer hooked up. Probably the trailer brake controller senses the electric brake.