Hello all. I have a 2000 crv I’m trying to splice in a four wire trailer harness. The wire connector behind the rear speaker has six wires. And all six seem to be connected to ground. Is this supposed to be correct??? I would think just one of them would be grounded
I can find the power wires There is a separate wire for tail and brake light, but thinking I use the tail light wire and the blinker wires are also used for braking lights. Do they automatically double as brake lights? Or do they get spliced in with the brake light wire? Thanks for any info you can give me

 

The wiring is shown in the owner's manual: