trailer wiring issue

i have a 2000 Bravada, AWD, 4.3l. heres my issue...i went to hook up a boat trailer yesterday and only the left taillight worked. then i pushed the brake down and nothing worked. i now cant get any lights to work on my trailer. i checked the fuses marked with a 'trl'. is there another mystery fuse i should check? should i cut the wiring and re-wire? i followed the wires underneath the bumper and there is just a sleeve they go into that runs along the frame. where do they connect in? i REALLY wanna go fishing tomorrow so i need help ASAP. thanks.

use a light tester to make sure you have power at the plug , it might be the boat trailer that has a bad wire

use a light tester to make sure you have power at the plug , it might be the boat trailer that has a bad wire

the trailer is fine. its my friends and it works just fine for him. i just re-checked all my fuses and theyre all good. i cut the wiring coming from the truck about 6inches short and the ground looks ALOT better. was really crusty at the original end. gonna rewire and check it out.