Yes and Yes!
I had problems with the brakes on my fifth wheel when I first brought it home, they barely worked! I reset them up but it still wasn’t adequate IMO. Upon further inspection The previous owner had fooled with the electrical connectors and when he replaced them he did not use waterproof connectors. Both ends of the wires that run through the axle were full of corrosion as were the connectors themselves. The point the wires enter and exit the axle can be areas of concern.
I took a quarter inch off of each wire at a time until I got to solid non-corroded wire, I did not use the wires that ran through the axle, I ran new 12 gauge wire over the top of the axle with wire loom and then zip tied that in place. I posted a link below to the electrical collectors are used, when you push the wires into them and screw them on it pops a small pocket of sealant that makes the connector waterproof. If you take them off do not reuse them use a new one each time.
If you don’t have self adjusting brakes
you should adjust them every year. If you replace them spend the extra money and upgrade to self adjusting. Below is a video that describes the process.