The most obvious culprit is the ABS suzie.
Edit now I see that it is drawbar trailers which you hook up to, so presumably the suzie belong to the trailer. In which case the socket on the back of the unit is likley to be suspect.
The most obvious culprit is the ABS suzie.
Edit now I see that it is drawbar trailers which you hook up to, so presumably the suzie belong to the trailer. In which case the socket on the back of the unit is likley to be suspect.