Ok I'm putting 6x9's in right now. Which wire is the negative? Both have stripes... one stripe is darker than the other.... on the rear driver's side right now...

 

Basic Audio
Rear Driver:
+ GY/LG
- GY/DG
rear Passenger:
+ DG/LG
- DG/GY

 

You can check my thread for the full wiring diagram.

 

You can use a meter. Turn the radio on and put the meter on the leads. If the meter reads negative, switch the leads based on the +/- of the meter lead colors, usually red and black.

 

The signal out to the speakers should be A/C.

 

usually the spaeker even OEM, will have a dot on it representing the positive,Even more basic................unclip the speaker connector, use a 9 volt battery with wires or a clip, touch the leads of the battery to the speaker for just one second a few times,and watch the speaker, the speaker will move out --in---out ---in, then look at the battery it will tell you on the battery which is positive and negative, if it goes in --out --in --out, you can do this while the speaker is still mounted in the dash or door also,with a flashlight and using the leads from the speaker that are disconnected from an amp.