Connecting 4-Way on Motorcycle to 5-Way on Trailer

Question:

I just got my 5 flat prong to 4 adapter and connected my motorcycle to my trailer and the 3 added lights on the back of my trailer arent working I know they work cause the guy showed me but also his plug on his bike was the same as on the trailer 5 flat. Is it possible that I could splice the blue wire to the brown for the extra trailer lights or do yall carry a 5 prong flat that I can plug in under my seat to replace the 4 flat prong

asked by: Ronnie L

Expert Reply:

I think what might be going on here is that your trailer uses separate wiring (which is what a motorcycle would typically use as well) but your motorcycle has combined wiring, or at least is equipped with a converter to combine it before the connector, which is why it's equipped with a 4-Way instead of a 5-Way. With a combined wiring setup the turn and brake signals on each side of the motorcycle are sent along the same circuit. This is why the lights aren't working correctly on the trailer when hooked up.

It would be pretty odd/rare for a motorcycle to be truly wired as a combined setup, so I think there's most likely a converter installed before the 4-Way to combine the circuits. You can check your wiring to be sure.

If this is the case, your best and easiest option will be to simply cut off the existing 4-Way BEFORE the converter. Then using the motorcycle's signal light circuit wires simply hardwire in a new 5-Way connector like # HM37908. You will just need to test the motorcycle wires for function to make sure you make the right connections to match how the trailer is wired up.

If you find that you have a different setup on the motorcycle (or trailer) please just let me know and we can go from there!

expert reply by: Chris R