The Dexter web site is a pain to use - you need lots of patience. I'm assuming you have found this document. There is a lot if info in it, much of which does not apply to TM brakes. But some of it does. In particular, it says that the current expected in each brake magnet is 3 amps, so you should be looking for a total of 6 amps.
https://www.dexteraxle.com/docs/defa...rsn=12dee048_0
It occurs to me that 11-14 amps might represent a dead short, with current limited by the wire resistance. This limiting is especially applicable if your Tow Vehicle has #14 or #12 wires from the controller to the back bumper. The TM is wired with #10, which is proper, but most tow vehicles are not. Who wired the controller wiring for you?
The presence of a short is easy to identify. Just disconnect the trailer from the tow vehicle, disconnect the TM battery, and measure the resistance from the brake line pin in the TM's 7-pin connector cable, to ground. Each brake is around 4 ohms, so the parallel pair should measure about 2 ohms. Anything less suggests the presence of a short.
Bill