I hooked up power, ground and 12v constant and it doesn't power up. Does the unit not power on if there are no speakers attached?

ScAndal

so you've got red and yellow to +12volts and black to ground? If the unit doesn't power up check the fuses on the harness. Any avic will power up without speakers hooked up to it. mine does every day and I have exactly 0 speakers hooked up to it.