wiring a rca converter to tock stereo there is 6 wires r rear +,-l rear +,- leaving 2 brown wires for what ?

Question

are they ground or what??

Answer 1

99% of the time, you can leave those wires unhooked; just tape them off and leave them alone. In hundreds of installations using line-out converters like you're describing, I've never connected the brown wires to anything at all. The instructions will tell you to leave them unhooked except in certain cases.

Answer 2

they are the ground noise isolator of the coil inside the hi/low interface you can ground them or use individual ground for each channel if the radio is old like 15 20 years old
good luck with the installation