This is probably a dumb question but I want to make sure I get it right. The speaker wire on a 2007 Frontier (from the door) is blue & red, is the red + and the blue - ?

Thanks in advance

HEre's what I have, and moved your post.

Audio/Mobile Video

WIRE COLOR POLARITY LOCATION

Battery YELLOW (+) RADIO HARNESS

Accesory GREEN/BLACK (+) RADIO HARNESS

Ground CHASSIS

THIS RADIO GROUNDS THROUGH THE CHASSIS MOUNTING BRACKETS.

Illumination RED (+) RADIO HARNESS

Dimmer GRAY (-) RADIO HARNESS

Amp Turn On GREEN/WHITE (+) RADIO HARNESS

LF Speaker (+) BROWN

LF Speaker (-) BLUE

RF Speaker (+) LIGHT GREEN

RF Speaker (-) RED

LR Speaker (+) GREEN

LR Speaker (-) BLACK

RR Speaker (+) GRAY

RR Speaker (-) ORANGE

Amp Location UNDER PASSENGERS SEAT

sorry about posting under the wrong heading...

I actually need to know which wire is what that comes from your door that hooks into the speaker. I have a blue & red wire for right rear and a blue & red wire for left rear. Not sure what I have for the front since I haven't removed the panels yet. I'm sure they are the same color though.

What you can do is take a 9 volt battery and touch it to the terminals of the factory speaker. If the cone moves outward then you have the battery terminals hooked up to the positive and negative terminals of the speaker. If it moves inward, then you have them backwards. Once you have determined the polarity of the speaker, you can then hook up your new speaker.

cool, thanks for the trick