1. The L&R speaker wires are NOT just for the front. They go to the preinstalled fader thumbwheel by all of your window switches in the center console and these two wires power all four speakers. Refer to you head unit instructions to wire up for a two speaker system.

2. The power antenna wire goes to the (usually blue in color and used as REMOTE) wire from the head unit and I do believe that is NOT the Accesory wire. The accesory wire is wired into a switched "hot" wire which is what will apply power to the radio when you have the car in ACC or running.

3. I'm not sure what you mean by your ground wires. The ground wires in these MB's are brown so be careful what you think is ground. You will have a negative(-) and a positive(+) for each of the two speaker wires and one ground for the power sources.

all together though you should have two speaker wire sets(4 wires total), a switched power(accessory), power antenna(remote), ground to a brown wire or negative side of battery, and a constant power(+12VDC) or off of the positive(+) side of the battery itself. Hope this helps you.

Also the remote wire could be used to power an amplifier eventually when you swich the radio on which is how this remote wire works. If you turn on the radio, power goes out through the remote line and switches on whatever it is connected to.

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1981 300SD