buzzard616 wrote:
First disassemble the plug to check all the connections inside.
If that all looks OK...
Then crawl around underneath and check the wiring connections to each wheel...
Next jack each wheel, one at a time.
Spin it and have someone stick a piece of wire into the #2 and #4 holes in the plug.
Brake plug
This should apply full brake power and the spinning wheel should stop abrubtly.
If this workes on all four the brakes are fine.
If all 4 wheels don't stop with same amount of 'force' then have the brakes checked.
Like others have said check the wiring under the trailer at each wheel. Instead of shorting the wire have someone pull the breakaway switch, it will check the wheels break operation/magnets & switch.