I have an 2016 F-250 Super duty Ford. My running lights on trailer don't work. My break stop and singles works fine. I looking where and what fuse number should I be looking for.

 

Have you checked your owner's manual? It lists the fuses in the Fuse Chapter.

You can download a copy here.

https://owner.ford.com/tools/account...h-results.html

check page 223 for the Battery Junction Box (BJB) fuses and relays.

check page 228 for the BCM fuses.

 

If it’s not your fuse....check the seal on the plastic harness. Had the same issue 2 weeks ago and the clip that holds the harness in had broken and everything was corroded. Had to replace the entire harness and whip with the connector.

 

Probably a fuse. Mine did this a few weeks back.

 

yes I did but nowhere for running lights for a trailer. I check all that had a trailer. It could be listed another way.

 

It's all new wires and harness. I have 12 volts on my break and single light at my truck but not getting any voltage for my running lights.

 

Check these fuses. Some may pertain to the problem, some might not.

BJB

#10 - 40a
#26 - 30a
#70 - 10a
#90 - 25a

BCM

#15 - 15a
#30 - 15a

 

Not to state the obvious but If they were just replaced could it be the butt connection?

 

The first place I look when trailer lights act weird.........check all GROUND connections.

 

I would start with the 7 pin connector at the back of the truck. Clean it and check for proper connections.

 

They list them by their proper name “park lamps�. Fuse 26 in the box under the hood.

 

To the OP, is this still an issue or resolved? If still an issue are you measuring with volt meter or going off what trailer lights are doing? Do you have another trailer you could use for testing? Is this the only trailer you have hooked up on this vehicle thus far? Only addition is to check for a relay 29, is it there, if so I’d swap with 30 or 31.

 

Check the Fuses & relays under the hood. I was having issues with lights on my trailer and found a bad relay.