Boat trailer wiring help please

[Majja]

Well I did not think something like this would lick me. I mean I can read a schematic and everything. So why is wiring a boat trailer so dang hard. Here is the issue I have. I went and picked up the universal 4 flat kit at sports. (my truck is already wired for the 4 flat) Well I get home rig up my nifty removable mounts for the top of my boat and wire the ligths up just as it says. It has a nifty little splitter so it goes like this.

BB _G Y_ BB

So that is brown brown open terminal Green and than Yellow Open Brown Brown. Pretty straight forward.

Now here is my issue brakes work great blinkers work great and last y running lights work great. So you are asking what is the problem. Well when I turn on the lights and apply the brakes I lose all my trailer lights, how ever the blinkers work just fine with the lights on. I have double checked the grounds, I know the truck side is good as I have towed other trailers with no issue.

Any ideas? If you need me to take some pics I can do that.

Just in ase you need to know the truck is a 1990 Chevy k1500

Thanks
Majja
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