looking for a link to wiring diagram for my 93 gmc looking for the color of wires to the speakers to see which go +/- for speakers.

I think most of those Haynes manuals at Auto Zone have wiring diagrams in the back of them.

Check the Autozone website, they usually have those on there.

Here you go.

1992-94 GMC Suburban Stereo Information
Constant 12V+ Orange
Switched 12V+ Yellow
Ground Black
Illumination Gray
Dimmer n/a
Antenna Trigger Pink
Antenna Right Front
Front Speakers 4" x 6" Dash
Left Front (+) Tan
Left Front (-) Gray
Right Front (+) Light Green
Right Front (-) Dark Green
Rear Speakers 4" x 10" Rear Roof
Left Rear (+) Brown
Left Rear (-) Yellow
Right Rear (+) Dark Blue
Right Rear (-) Light Blue