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Discussion Starter · #1 ·
Upon plugging in the flat trailer plug the correct way, the trailer running lights do not work. On my new 350 Ford heavy duty truck the fuse explanations do not direct towards trailer running lights. I located both fuse boxes and checked the most obvious once. the fuse box inside the truck is extremely hard to access. Is there a wiring diagram anywhere? Can anyone point me in the right direction? Thank you, Please help.

Roland 2013 F350 Lariet Super Duty Diesel
 

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Discussion Starter · #3 ·
The 7 pin exit works, however there is no contact on the flat plug.
So my stock trailer likely will work, however my boat trailer has a flat plug.
 

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The 7 pin and 4 pin connector should be connected together near the bumper, I doubt that they would both be ran separately back to a fuse block.

Do you have a test light that you can use to determine if it is the plug or the trailer, or does the trailer work on another vehicle?
 

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Discussion Starter · #5 ·
Yes, they run together. Funny the flat plug gives me no light on the three pins when ground is connected to ground (the fourth pin "female").
Yes the trailer lights work if connected to another truck.

This is how I got the problem in the first place; one early morning I tried to plug inn the flat plug in the dark, that was a mistake, because I tried to connect the wrong way around, I knew immediately because of a spark at the plug that I plugged it inn the wrong way. since then I have this dilemma.
 

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Just for giggles and until someone else chimes in here that knows this year of a truck can you plug your other trailer into the 7 pin and see if it has running lights.

If the stock trailer running lights work then I would suppose that it is a wiring problem since there should only be one fuse for the running lights. Also if the stock trailer running lights work on the 7 pin plug you might just pick up a 7 pin to 4 pin adapter to get the boat trailer lights working.
 

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Discussion Starter · #7 ·
I purchased the 7-4 adaptor, no go.
7 pin does not work on the other trailer.

I think it has to be a Fuse, however which one. It is hardly possible to che them all because they are so hard to reach.
It's the running lights on the trailer only that does not work, I wish theFord Book would be more accurately describing this particular fuse location or number.
 

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Discussion Starter · #9 ·
Your guidance was great, thank you very much.
It was not #29 but #26.
Because of your help I was able to resolve my problem, again thank you very much.

Roland
 
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