Trailer 7-Pin connection

[Rhinebeck01]

@Fgonzal2
For your records...

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[grimmjeeper]

I would suspect that the trailer 7 pin connector is not wired correctly

That could also be the case. But the tester verified the plug on the other truck and it works. So it's unlikely to be the problem.

 

[gm920]

That could also be the case. But the tester verified the plug on the other truck and it works. So it's unlikely to be the problem.

I don't see where the OP verified the GMC plug, only the JLU and that the trailer works on the GMC, my next step would be to verify the trailer wiring is standard

 

[grimmjeeper]

I don't see where the OP verified the GMC plug, only the JLU and that the trailer works on the GMC, my next step would be to verify the trailer wiring is standard

Yeah, that wasn't entirely clear at first. Worth looking in to.

 

[gm920]

Yeah, that wasn't entirely clear at first. Worth looking in to.

Agree, probably easier to put the tester on the GMC

 

[Fgonzal2]

Just verified that it is in fact seated correctly and it still does not work.

 

[Fgonzal2]

I don't see where the OP verified the GMC plug, only the JLU and that the trailer works on the GMC, my next step would be to verify the trailer wiring is standard

When the trailer is connected to my fathers GMC via 7 pin it works fine. When I connect the same trailer via 7 pin to the JLU it does not work. I used a curt 7 pin tester on the JLU and all 6 lights are working properly. Next is to get a 4 pin and see if it works that way. That may be the work around.

 

[grimmjeeper]

When the trailer is connected to my fathers GMC via 7 pin it works fine. When I connect the same trailer via 7 pin to the JLU it does not work. I used a curt 7 pin tester on the JLU and all 6 lights are working properly. Next is to get a 4 pin and see if it works that way. That may be the work around.

I'm skeptical that the adapter will work. It seems most likely that both the truck and the trailer are incorrect in a way that matches each other but nothing else.

 

[Fgonzal2]

I'm skeptical that the adapter will work. It seems most likely that both the truck and the trailer are incorrect in a way that matches each other but nothing else.

Something is definitely off and seems as everything is pointing back to the JLU. My FIL and cousin have both used the trailer with their own vehicle in the past and it worked fine.

 

[gm920]

When the trailer is connected to my fathers GMC via 7 pin it works fine. When I connect the same trailer via 7 pin to the JLU it does not work. I used a curt 7 pin tester on the JLU and all 6 lights are working properly. Next is to get a 4 pin and see if it works that way. That may be the work around.

Connect the 7 pin tester to the GMC and see what you get

 

[Fgonzal2]

Connect the 7 pin tester to the GMC and see what you get

I will try that as well.

 

[grimmjeeper]

Something is definitely off and seems as everything is pointing back to the JLU. My FIL and cousin have both used the trailer with their own vehicle in the past and it worked fine.

Are they using factory plugs or did they add aftermarket plugs? It's easy when you're wiring them up to do it backwards.

 

[Fgonzal2]

Are they using factory plugs or did they add aftermarket plugs? It's easy when you're wiring them up to do it backwards.

They are all factory plugs.

 

[Fgonzal2]

I am wondering if it’s just the 7 pin itself. Maybe if I purchase another 7 pin and swap it out that may work.

 

[Fgonzal2]

This is the adapter it is a 6 round to 7 blade. Would I need a different adapter for it to work with the JLU?

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