Red is positive right...Whats negative and whats ground....I think yellow is negative but wana get your advice before i blow my 500 dollar sony deck.

-Daryl

 

Black is ground. I've transfered my Pioneer cd player several times between cars and there was a power wire, a ground wire, one unknown wire with a fuse and the rest were speaker wires. I never figured out what the wire with a fuse was for...I haven't had any problems though.

 

If you are talking about aftermarket stereo wire colors, Red is switched (accessory), yellow is constant (12volts+) and black is ground.

 

How do I wire the stereo in so that it only come on when the key is in the acc position? In all the cars I installed this stereo in, the radio can turn on without the key. I just left it like that. I'm sure it has something to do with that myterious wire I don't use...

 

spend $40 bucks and get a stereo shop to put it in. Ive found taht the big name brand places do cheap work and usually screw things up. So I prefer the smaller private operations. Also if you have the power antenna you need to swap a couple wires in the harness so you dont pop a relay. Mazdas power antennas in 2nd gens work backwards from the rest of the world.

 

Okay step by step power wires hook up for aftermarket radios:

Mazda Stock Ltblue/White hooks up to the red ignition lead of the aftermarket stereo

mazda Stock LtBlue/Red hooks up to the yellow constant 12volts wire of the aftermarket stereo

Black wire of the aftermarket stereo goes both to ground and 85 & 30 of a extra relay to run up the factory power antenna. I like to use the 10mm bolt under the center console side front access panel as a good ground source.

The Mazda stock LtBlue/yellow wire to 87 of the extra relay for the power antenna.

The aftermarket radio's Blue or Blue/white power antenna output goes to 86 of the extra relay to run up the factory power antenna

 

did you get a wiring harness adapter(please tell me you didn't cut of the factory wiring harness), if you get that, than all you gotta go is match up the color and connect them