2005 4runner 7 way plug trailer not working

[Bptbd]

I have a 2005 4Runner SPort edition V6 with the 7 way blade plug in style trailer wiring. I have always used an adapter for the 4 way plug.
I can't get any trailer lights to work on this 4 runner. It worked great 6 months ago and then went to use a different trailer and no lights working on trailer when hooked to vehicle. I do know all of these trailers work on different vehicles.
Is there a specific way of testing the wires going to the plug in. I do have a circuit tester light and tried that but nothing at all. I would like the vehicle to stay with the factory 7 way plug and just use an adapter unless there is something more stable and more user friendly out there.
I am asking for help that if anyone could possibly know why we have no lights at all and that if there is a control box on this vehicle where it is?
Please help. I do not want to take it to the dealer just to cost 400 dollars for them to ruin it.
Thank you in advance.

 

[Plumber]

I have a 2005 4Runner SPort edition V6 with the 7 way blade plug in style trailer wiring. I have always used an adapter for the 4 way plug.
I can't get any trailer lights to work on this 4 runner. It worked great 6 months ago and then went to use a different trailer and no lights working on trailer when hooked to vehicle. I do know all of these trailers work on different vehicles.
Is there a specific way of testing the wires going to the plug in. I do have a circuit tester light and tried that but nothing at all. I would like the vehicle to stay with the factory 7 way plug and just use an adapter unless there is something more stable and more user friendly out there.
I am asking for help that if anyone could possibly know why we have no lights at all and that if there is a control box on this vehicle where it is?
Please help. I do not want to take it to the dealer just to cost 400 dollars for them to ruin it.
Thank you in advance.

You could try the relays in the little box beside the main distribution block under the hood....its the little block on the opposite side than the battery. I would recommend removing the negative battery cable before you take them out.

 

[Bptbd]

Thank you I will try that. If it isn't the relay do you have any other suggestions that it could be?
Thanks

 

[Plumber]

Thank you I will try that. If it isn't the relay do you have any other suggestions that it could be?
Thanks

If you trace the wires coming into the 7pin plug there are two harnesses that are snapped onto the frame on the driver's side. check those for any burnt pins indicating a short. Also check continuity from the seven pin to the contacts inside of those harnesses.