Question on 5th wheel brakes

However, the trailer does not seem to offer any resistance. I am finding that I have to put a block under one of the tires on the cyclone to relieve the pressure. Is there something wrong with my braking system?

i have a 2013 Chevy 3500 with a built-in brake controller

Yeah...you truck controller or the trailers brakes have a problem.

I've never had a trailer (rv trailers/commercial trailers ) from the factory that the brakes worked like they should.
Part of the problems was the use of small dia wiring for the brakes. The biggest culprits was the clam shell type connectors that rv and some low cost flatdeck trailer mfg were using. After time and miles of use clamshell connectors can get corroded from salt water spray. This can cut amps to the brakes even tho they check 12v.

What I did with every trailer before I put it in service was cut and remove all crimp connectors and solder all connections. You also need to address the wiring where it goes into a drilled hole in the axle tube ends. AS the wire is pulled through that hole it can strip the wiring insulation off causing one or more brakes not to work 100 percent or not at all.

The 2015 trailer is old enough for those clamshells to possibly have some corrosion ...depending on how its been used.

I would run a amp meter check at each brake and see if your getting the right amount of amps. Then R&R from there till you find a weak link in the system. The axle mfg websites usually have info on amps for brakes on each size axle.

Every trailer I've owned or leased from employees with 12v electric/magnetic brakes and good 12v controllers the brakes worked forward and backward after a 1/2 wheel revolution. Granted in reverse as another poster mentioned the trailers brakes has less clamping force but reverse means backing speeds.

Like a dot officer said at my first new entrant audit before going into service was if the trailers brakes don't stop and hold the trailer going forward or backward then get them fixed.