The color of the wire depends on which end you cut off the phone cord.
Look into the V1 Accessory jack on the harwire adapter or on the cigarette lighter adapter or the V1, with the pins on the top of the jack. The ground will be the second one from the left, and the mute will be the far right one (4 conductor wire). Line up the plug and check the colors of the wires before you plug it in.
You should probably still check it with a multimeter or a test light, just to be safe. With a multimeter you can just have the line plugged into the cig adapter and easily figure out which one of the two middle wires is ground. If not, you can use a ground elsewhere on your car.
Once you figure out which is the ground, the one you want to attach it to will be the line furthest from it.
DATA GND +V MUTE
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