How to Make a 6-Way Square to 4-Way Flat Trailer Wiring Adapter

Updated 03/26/2020 | Published 01/28/2012

Products Featured in This Question

6-Pole Square Trailer Wiring Connector Kit (Car and Trailer Ends)

(197)

$5.53

Quick Fix (TM) 4 Pole Flat Car and Trailer Ends

(137)

$10.25

Hopkins Endurance 4-Way Flat Trailer Connector w/ 48" Harness and Ergonomic Pull

(52)

$11.06

Hook Probe Circuit Tester

(60)

$12.27

Question:

We have a 2004 Monaco RV with a 6 pole square socket. We have a utility trailer to pull our toys that has a 4 pole flat plug. We are unable to find an 6 pole square to 4 pole flat adapter.

asked by: LaVaun S

Expert Reply:

The 6-Way square trailer connector is not used by a lot of trailer manufacturers. A lot of Jayco trailers may have them but mostly you come across the 4-Way flat, like what you have on your trailer, and the 7-Way blade for RV applications.

What I recommend is to convert the 6-Pole on the Monaco to a 4-Way. You can do this very easily by removing the 6-Way plug, and then testing the wires for function using a circuit tester like # 3808 if needed before installing them in a new 4-Way, # HM48030. The 4-Way vehicle end functions will be oriented in the 4-Way as follows:

Exposed pin = ground (white wire on harness)
Next pin = running lights (brown wire on harness)
Third pin = left turn and brake lights (yellow wire on harness)
Last pin = right turn and brake lights (green wire on harness)

The other wires can be taped up and stowed out of the way.

Since so many more applications use the 4-Way flat, this will be the ideal option. But, if you do not want to remove the 6-Way on the RV, you can make your own adapter. You will start with the 6-Pole Square Trailer Wiring Connector Kit, # 37995. Plug the trailer end into the connector on your RV, then use a circuit tester like # PTW2993 if needed to test each wire.

Next, use the vehicle end in the Quick Fix (TM), # 48195, and insert the wires as described above. The other wires you can tape up because they will not be used by the 4-Way. Once you have made all of the connections you will have made your own adapter.