How to Find Correct Wiring For Hooking up Hopkins 5 Flat HM37918

Updated 07/20/2021 | Published 07/19/2021

Question:

My plug on my trailer broke so I had to end up replacing it. Can you tell me what colors go to work in this photo?

asked by: David

Helpful Expert Reply:

I can help you figure out how to determine which wires to hook up a 5-flat like the Hopkins # HM37918, though we don't have any way to know the functions of your trailer's wiring, because there is no universal color code, as helpful as that might be.

What you need to do is either trace the wires back to their lights if possible, or test the wires for function using a charged 12 volt battery and a jumper cable, applying 12 volts to each wire. This is going to tell you what their functions are; that will allow you to hook up your new connector.

I have added links below to a couple help articles on trailer wiring for you to check out as well which I highly recommend looking through.

expert reply by: Kyle S