first thing that popped up on google
see if thats right, otherwise use a multimeter like ur meant to when dealing with wires
1988-91 Honda Civic Stereo Wiring
Constant 12V+ Blue/White
Switched 12V+ Yellow/Red
Ground Black
Illumination Red/Black
Dimmer n/a
Antenna Driver's Pillar
Front Speakers 6 1/2" Doors
Left Front (+) Blue/Green
Left Front (-) Gray/Black
Right Front (+) Red/Green
Right Front (-) Brown/Black
Rear Speakers 6 1/2" Rear Deck
Left Rear (+) Blue/Yellow
Left Rear (-) Gray/White
Right Rear (+) Red/Yellow
Right Rear (-) Brown/White