Trailer not registered as connected

[paulbeauchemin]

Have a 2015 F350 towing a fifth wheel

When I used to connect cord to the truck the dash would display "trailer connected" and engage brakes

Now that alert is not displayed and brakes do not engage

- trailer lights work
- I've checked the fuses that seem to be related to towing and they all are good
- tried cleaning the plugs

Any ideas what is wrong?

[2PawsRiver]

When I was test towing a Jayco 4113, it displayed the brakes were not connected, lights and all worked. When I returned the tech said it was because there was not a battery on board. Not sure what you are towing, but maybe check your trailer battery connection if it's a Jayco.

[enblethen]

Does the truck have a factory brake controller? Some trucks have two fuses for the brake controller, one control and one brake poweer. check owner's manual.
Just because you have brake lights doesn't mean the brakes have power.

[romore]

Have you got a test light or VOM? Have somebody apply the trailer brake and see if you have power at the receptacl then work back from there. I would suspect the trailer brake fuse but you say you have checked that.