I bought my son an 85 300zx non turbo. The antenna was messed up so we bought an after market power antenna. The antenna has one red, one green and one black wire.

The pics below show the wiring harness that went to the stock antenna.

Using a volt meter I have determined that the red wire is constantly hot (11.9 VDC). The black with red stripe wire has 10.9 VDC when key on. All other wires have negligible voltage, some positive and some negative.

I thought the black with red strip was the switch wire but the antenna will not extend using 10.9 VDC. It will extend if I connect both the green and red lead wires to the red 11.9 VDC wire of the wiring harness.

Any reason for the black red wire to be 10.9 VDC?

Any idea how I should wire the antenna using the existing wiring harness?