Trailer brakes
 

I bought a new plug to hook up to the boat trailer and when i was hooking it up i noticed on the old one the blue for the brakes was hooked up for back up not on the brakes. So on the new one i hooked it up correctly so the blue is on the electric brake connection. When i picked up the boat from the shop and i got home as soon as i started to back up the brakes locked. I have no idea why so i recconected the blue to the back up and it worked no problem. I'm not sure what is going on. Does anyone have any good tips or ideas on this issue?

It is hooked to the back up lights so when you shift into reverse (back up lights come on) it disengages the surge brakes.

With the blue wire connected to it, it is in constant bypass mode since the blue is a constant 12v signal. As said above, it should be connected to the back up lights so it only gets a signal when in reverse.

it is hooked up on the back up lights now and works fine. My concern is that when i'm driving around are the brakes always on.

so it was originally hooked up correctly on the back up lights? Why is there a brake connection on the plug when we use the back up light connection?

The brakes on boat trailers are not electronic, the are surge brakes so they don't need power to tell them to break.

The blue wire only locks the breaks out when in reverse, that's why it's connected to the backup lights.

Thank you guys for the help. I'm new to owning a boat and was not sure how it works.