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Replacing 6-Way on Trailer With 7-Way Connector


I have a 6 way wireing plug small round and want to replace with the large palstic RV 7 round flat spade but the wires on the trail in the small plug do not color code to the pin settings on the large RV should I still go by color code on the plug?


Expert Reply:

Since wire color codes are NOT universal, we always recommend wiring by function, rather than wire color.

If you look at the Trailer Wiring FAQ article I have linked you to, you can see some diagrams showing the proper way to wire a vehicle and trailer side 7-way trailer connector.

If can you open up the existing 6-way connector on your trailer, take the housing apart and look at the terminals the wires attach to. In many cases, they will be labeled like what is shown in the FAQ article. You can then label each wire, so they are connected to the proper terminal when you install the 7-way. If the terminals are not labeled, you can physically trace each circuit, or you can use a 12 volt battery, attach the trailer ground to the negative post and apply power to each circuit to see which function powers up.

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expert reply by:
Mike L

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Follow up Questions

James P.

on my 6 way connector i do not have a blue wire i have red,green,yellow,brown, white , and black i am going to a 7 way plug so how would i wire a 6 way adapter ?

Etrailer Expert
Reply from Chris R.

The red wire is most likely the brake output circuit but I HIGHLY recommend that you actually test each one for function using a circuit tester to be sure.

Rick G.

I have a dump truck with a 6 pin small round receptacle I need to replace with a 7 blade receptacle so my trailers will work. Is it possible with the 6 pin to 7blade that all the functions will work on the trailer?

Etrailer Expert
Reply from Jacob H.

Yes, you can convert the 6 pole to 7 pole with # 47435.

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