Trailer Brakes Locking Up (1 Viewer)

[Hobbyfarmer]

I have a 1986 trailer with 2 5000 lbs axels with brakes on the rear axel and a 6 way round connector.

Since 2003 I've owned pick ups with the newer 7 way round connector and I use a 6 way to 7 wat adapter. When I hook the trailer up to the truck, the brakes instantly lock up without the brake pedal being pressed and will not release until the connector is disconnected. All lights work correctly. Ive even hooked it up to different trucks and tried adjusting the brake controller on each truck . It seems like all the wires are connected correctly but maybe I'm missing something. Any help would be appreciated

 

[balu4k]

Was this setup working correctly with the same truck, trailer and adapter combo and this issue just started coming. if that is the case may be there is a short circuit some where in the line and that conducts the current to the brake wire. if you have 12 v battery try feeding one line at a time in trailer female pin one by one and see which one is locking up the brake.

 

[Hobbyfarmer]

Was this setup working correctly with the same truck, trailer and adapter combo and this issue just started coming. if that is the case may be there is a short circuit some where in the line and that conducts the current to the brake wire. if you have 12 v battery try feeding one line at a time in trailer female pin one by one and see which one is locking up the brake.

I believe the last time they worked wes when I had a 6 way male connector on the truck but I'm not completely sure on that - its been awhile. I only have one wire coming into the connector so I would have to cut into a juction somewhere under the trailer to isolate the individual brakes but both brakes are activating when I plug the connector in so maybe that answeres that question w/o testing with a battery.

 

[balu4k]

I believe the last time they worked wes when I had a 6 way male connector on the truck but I'm not completely sure on that - its been awhile. I only have one wire coming into the connector so I would have to cut into a juction somewhere under the trailer to isolate the individual brakes but both brakes are activating when I plug the connector in so maybe that answeres that question w/o testing with a battery.

I doubt the adapter has the wrong wiring connection.

To find out first make sure, the running lights, brake lights, turn lights and back up lights are all off on the tow vechile and check if the brake still locks up. if that is the case, then the Aux/ charging wire is the one that is wrongly mapped to the brake wire at the adapter. Try pulling the fuse for the aux/charge wire at the truck and see if it unlocks the brake.