As I went under the trailer to fix something, I have noticed that only the right side drum/brake is wired, the left side has the wired trimmed. Is that normal? Thanks.
The brake wiring could be inside the axle tube, or the wiring could be cut like you're suspecting. An easy test would be to hitch the trailer up and connect the umbilical. Then have someone slide the manual brake lever to full brakes. Put your ear by the suspect hub and see if you hear a hum from the brake magnet. If you hear the hum the wiring is hooked up, if you don't hear anything then you'll have to pull the wheel and hub.