Setting up Prodigy brake controller

2 thoughts.

Had the same problem with mine, so you are not alone :o)

Found the brakes needed adjusting. Adjusted them up a little and all OK.

Or,
maybe not getting full voltage through.
Can you hear them working if some one lese puts their foot on the brake when you are standing next to the trailer?

Probably brake adjustment or voltage loss....
Many electric brakes will not lock up with full voltage. Can be a problem with brake adjustment, or faulty brakes, or low voltage AT the brakes.
If you see full voltage on the display, the prodigy can do no more- after that it's up to the brakes. They may simply need somemore "bedding in" but I would be suspicious of voltage drop from the controller back to the brakes- there is plenty of potential for voltage drop with a long wire run and plug connection.

When the brakes are new, they are not fully bedded in - that applies to the magnets as well as the brake friction surfaces.

I had the same thing - brakes wouldn't lock until fully bedded.

As mentioned, make sure your wiring is good - at least #5 wire from the battery to the prodigy and then to the brakes, as well as a #5 earth wire back to the battery on the car from the trailer. DON'T rely on the towball to provide the earth - it won't. And if you have a tregg hitch, you will have even less chance of an earth.

Have a prodigy and a KK CT and have never got the brakes to lock up on the tar, even though they still work pretty good..
Adjusted up the brakes, checked voltage etc....maybe the setup of the brakes themselves ??