I have an 85 Z28. Has just am/fm. I obtained an OEM am/fm cassette. When I pulled the original radio, some work had been done.
The original black, white, blue cables were connected to the AM/FM radio but the 2-wire white connector block on the back of the radio
was not. There was a jumper wire from the battery plug of the fuse box to the orange wire on that connector. So it appears the orange.
wire of that plug needs 12volts. Anyone know what the brown wire for that connector is for? The cassette radio plays fine but nothing
is connected to that brown wire. I searched inside the dash and could not find the female end. It has been cut out of the car for some.
reason. Neither radio will play unless you hook up the jumper wire to the orange wire on the plug. Just wondering what the brown wire
is supposed to be connected to?

 

BROWN wire is the "headlight ON" signal to the radio; it's used for dimming the radio display when the lights are on at night.

ORANGE wire is power at all times; retains station & clock memory.