7-pin adapter issue - signals work but not night marker lights

bhollehday

Petty Officer 3rd Class
Joined
Aug 16, 2017
Messages
77
I recently bought this from amazon:

https://www.amazon.com/gp/product/B001F0GE8G/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

I bjust bought the boat and been using a 7-pin to 4 pin adapter and everything (besides the brake lock) worked great. I bought the adapter and i think the brake lock is working, but now i have no lights with my headlights on. Only when i signal or brake. Could I have bought the wrong adapter? Is there some wiring diagram I need to follow? Its just a normal dual axle hydraulic disk brake 22ft trailer.
 

bigdee

Commander
Joined
Jul 27, 2006
Messages
2,665
Sounds like the wiring configuration on the receiver plug doesn't match the adapter. Look on google images for proper 7 pin wiring diagrams.
 

briangcc

Commander
Joined
Jul 10, 2012
Messages
2,091
To me that sounds like a wonky grounding issue. What happens if you add a ground wire from the trailer frame to the vehicle (for testing purposes)? Do your lights function as they should? IF they do, you can buy large alligator clips (spring clips) and add it to one end of your jumper wire to make sure you have a good ground.

I had an issue where ground wasn't passing on my Four Winns trailer and that's how I resolved it. Ring terminal on one end secured it to the trailer, the other had a large spring clip I connected to the hitch.

Otherwise, IF this is a used trailer of unknown vintage, I'd start inspecting the wiring to make sure it didn't chafe and start another issue. I had this issue on my Four Winns as well as the wiring inside the swing away tongue was chewed up mightily. Ended up replacing it all as it was an electrical short waiting to happen.
 

Leardriver

Petty Officer 1st Class
Joined
Oct 7, 2008
Messages
373
Do you have a test light, or second choice, a volt meter? You are looking for power along the brown wire for running lights. Is power going in to the trailer side brown wire?
 
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