Trailer running lights inop

My 2005 XSP has a round 6 prong electrical socket for trailer connections. My boat trailer has a flat 4 connector. I purchased a adapter to mate them up.
My problem is that I’m not getting any running lights. The brake, and turn signal lights
work fine. When I turn on the headlights fir the truck, the trailer running lights Don’t come on.
I have another truck and all the trailer lights work when I use that vehicle.

where do I start?

 

Is this a factory tow package? It should tell you on the Toyota site when you plug in your Vin.

 

I think it’s a factory tow package. It looks factory under there

 

Have mine off to paint and should be 7 connectors counting the center back up lamp if it’s tow package. The other item is a 7 to 4 pin plugin

 

clean the truck plug and your wiring adapter really well. Wiggle it around a good bit when you plug it in. If still not working, look in your manual and check any of the related fuses. If all that checks out and still an issue you will need to start checking individual pins/current on the truck plug to see if you have power to run the lights. If not, the wire that handles that could be broken, pinched, etc.

But usually, it is a build up of crud or corrosion up in the truck plug/pins or the trailer.

 

Ok, mine looks like 5he picture above. Is there a trailer running light fuse I can check?

 

The green(top left pin) if indeed like above pic, is your tail lamp. If you have a meter, turn lights on, should have 12 vdc at top left pin(green)

 

I will check that. Thank you for nice diagram.

 

UPDATE I checked all the suggested items. Turned out to be a blown 30 amp fuse.
It was under the hood.

 

Hmmm....was it the 30A Towing Tail fuse and if so, have you checked wiring to determine what might have caused a 30 amp to blow ?

 

It’s a new to me truck. I’m going to tow my boat tomorrow and see what happens.
If it’s fine, then it was a fluke and never find the fault.

 

All lights check out. Hello new to me boat!