Create your own cord or replace the damaged ends on your RoadMaster 4-wire straight and Flexo-Coil electrical cords with these 4-pole, male and female connectors.  Call 800-298-8924 to order Roadmaster Accessories and Parts part number RM-910030-4 or order online at etrailer.com.  Free expert support on all Roadmaster products.  Guaranteed Lowest Price and Fastest Shipping for RoadMaster 4-Wire Connectors - Trailer and Vehicle Ends.  Accessories and Parts reviews from real customers. 

To adapter I recommend to be able to convert a 4-way round female connector to a 4-way round male connector is by using the RoadMaster 4-Wire Connectors, part # RM-910030-4.  This has both the female and the male plugs separate. 
You would need to run the appropriate wires into the rear of each connector using wire like part # DW04923-1.  This is jacketed 4-wire and is 14 gauge.  This is sold by the foot. 
When wiring connectors I recommend using a circuit tester like part # 3808 to...view full answer...

Although we do not carry a wiring harness/adapter that will allow you to split the 5-flat on your tow vehicle to allow you to connect to both the 5-flat on the trailer and the 4-round on the boat, I have a solution for you. 
You will need the RoadMaster 4-Wire Connectors, # RM-910030-4, Jacketed 4-Wire (sold by the foot), # DW03240-1, and the Deka Heat Shrink Butt Connectors, # DW05745-5. 
I recommend that you splice into the wiring, behind the 5-flat on your trailer, in order to add...view full answer...

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