Issues backing up

[WacoWildcat]

Boat is a 2017 Phoenix 920 with a marine master trailer. Noticed over the weekend when I was backing down the ramp I had to gas it to get it to go down the ramp in reverse. It wasn’t locked up but maybe it almost was? Anyone have any ideas? Oddly enough when I backed it into the garage when I got home there were no issues. Part of my drive is uphill too. Can you hear or see the brake release when the truck is put in reverse? I understand there’s a solenoid that fires when reverse is engaged. Thanks for any help or info!

[WisconsinF]

Yes, there is a solenoid that keeps the brakes from working when you put it in reverse. (works off the reverse light circuit) However....do you have that connected from your car/truck to the trailer. I had to buy a kit to add that 5th wire to mine. Trailer was a flat 5 wire plug, truck was only a 4.
Or in other words really need to know how your trailer wires are connected to your truck.

Have one of these just in case.
https://www.ebay.com/itm/LOCK-OUT-KE...kAAOSw8wFbAasu

[Texas Larry]

If your solenoid or reverse light circuit is not working, you should be sliding the tires when you try to back it up. You can test it by just disconnecting the trailer plug from the truck and try to back up a little. It will let you know if your brakes are working.

[billnorman1]

Under no circumstances should trailer brakes engage when backing down a ramp. Maybe it didn't want to get wet.

[WacoWildcat]

Lol. I wonder if something else is going on and the brakes are just sticking? I definitely had to give my truck gas to get it in and when loading up that day a guy came over to my partner and said it looked like the trailer was locking up. Truck has the round plug as does the trailer which covers all the wiring required for this trailer plus some. I didn't notice any issues when coming home or backing in the garage. I'll see what happens next time out. Thanks.

[Tom Edwards]

feel and/or look under the coupler to feel the plunger, then push up on it. if the brake cable has been pulled the break-a-way brakes could be applied. been there, done that, once. if you pull the cable too much, or step on the cable while stepping over the tongue, then it'll trip the break-a-way.

[billnorman1]

There's a weird one in a zillion chance that your ground wire is weak and the trailer is grounding through the ball. Then when you backed up, the trailer developed slack in the ball fit and the reverse solenoid locked up, however the trailer tongue has to be compressed to make pressure in the brake line.
What ever the situation, it is weird and I'm glad I'm not there or I'd try to find out why, and that's work.