Sorry dude. Audio is AC. Your voltmeter won't display polarity when measuring AC because the polarity is always changing (alternating).
Originally posted by marcopolo
The easiest way to determine + and - on your stock wires is to connect some voltmeter to it. Then run sum tunes and connect the voltmeter to the wires. You'r display should show either +xx.xx Volts or -xx.xx Volts. ...
1999 Buick Park Ave Ultra
Head Unit: JVC KWHDR720
EQ: Audiocontrol EQL
Front Stage: Hybrid Audio Technologies Imagine 5.25 mids, Morel Maximo tweets
Sub Stage: Boston G3 10", 0.5 cu ft sealed
Amp: PPI Phantom 900.4
Rear Fill: Boston SE953 6X9's