Marine Master Trailers utilizes different types of wiring harnesses and plugs for various trailer models. Wire colors are:
| White | Ground |
| Brown | Running Lights |
| Yellow | Left Turn and Left Brake |
| Green | Right Turn and Right Brake |
| Blue | Backup Lights and Solenoid Lock Out (disengage brakes while in reverse) |
| Optronics A30W5BL2BP | 34′ Jacketed 5-Way Wiring Harness with 7 Pin blade connector (trailers with brakes and/or backup lights) |
| Optronics A57CCB | 5-way flat to 7-way round, coil cord |
| etrailer.com HowTo | https://www.etrailer.com/faq-wiring-5-way.aspx |