PJ trailers are usually very well made and will last you for a long time if you take care of them. The dim lights were probably a result of a bad connection or improper ground connection. Check your wiring for a short. The trailer will have a three wire set; Green is the right side of the trailer's brakes and turn signal; Yellow is the left side for brakes and turn signal lights; the Brown is the running lights. The left and right is determined by standing behind the trailer and looking forward to the tongue.
A new axle is the best way to get electric brakes since the brake wire is inside the axle tube to get power from one side to the other. A 3,500 lb brake axle should be no more than 150.00 without springs (Note: Buy the Easy-Lube axle to insure you get grease to the back bearings when you do your ANNUAL axle service). You can use your springs that came with the original axle. The brake axle is directional and you must mount it with the right and left brakes on the corresponding side of the trailer or they will not work. Additionally, you will need to install a Break-a-Way system which consists of a 12 v small battery and a snap switch to activate the circuit and stop the trailer if it breaks away from your vehicle. This will be about 60.00. You will need to install an additional wire pair to operate the brakes, one hot and one ground wire. This should make you 50 state legal if you are less than 8'wide and16' in length.
This will call for the 7-prong plug to run the three basic wires, the two wire brake system, a ground wire and a hot wire to keep the Break-a-Way battery charged. It is not difficult to do if you want to invest in the trailer. I used to own a trailer manufacturing and axle distribution company (31 employees) as part of my flying operation. Personally, if you are going to haul other riders bikes I would suggest a two axle trailer since if you have a flat on a single axle trailer it becomes pretty uncontrollable if you are heavy and are at speed and you also have the ability to carry up to 7,000 lbs which includes the weight of the trailer. Good luck in your endeavor.
2004 XR650L Heavily Farkled.