Evan

Ahhh the wonderfull job of the volvo radio harness lol, I have replaced the radio in both of my 740 volvos, 1 a turbo and on ea non both 86's same wires, Most of the wire pull a dasiy on you going through a factory amp under the stering coulm, can see them if you remove the drivers side under panal easy to get to, but if no one ever tells you this puppy has to come out when you replace it with another unit. From my head the yellow will never be used again thats a wire you can cut out as all new system have there own lighting in them, the single ( dasiy loop ) red one is for the antenna, the orange is a hot the black ( dasiy Loop ) is the ground and i believe its the green is the other hot, the rest are you speaker wires. Best bet if your thinking of replacing the system is to get the Radio Harness with yyour new system, you can pull all the wireing out to the last connector and plug in the new harness and just match the harness wires up to your radio, ive done it both ways much easyer with the harness. But all in all the only one ending up not used is the yellow.

Jason

86 740 Ti 230000

86 740 GLE 136000