Ok, this is what you do:
First, get rid of those connectors, but label the three in the black connector: yellow=power, black=clock(for CD player), gray you can cap off.
Second, you need to know what wires go where. I crawled under my dash to check and here is the list:
!!THE WIRES WITH TWO COLORS ARE THE NEGATIVE POLES!!
Yellow w/ Yellow/brown - REAR LEFT
Light Blue w/ Lt. Blue/dark blue - REAR RIGHT(I think you said you had a light blue/gray..this is the Light Blue I mentioned)
Tan(negative pole) w/ gray - FRONT LEFT
Green w/ green/dark green - FRONT RIGHT
Yellow wire in Black connector - power source
Black wire in Black connector - clock for CD player
Gray wire in Black connector - useless; cap it off.
Third, it'd be wise to make a list that explains which of the CD player's wires attaches to your trucks factory wires for each channel. The owner's manual to the CD player should tell each wire apart from the rest.
Finally, find a good ground(you can just put it under a screw some place) and begin splicing all of the wires together. You might want to get power to it first and test each channel before you splice everything together. Hope this helps you and good luck!
Just IM me at AIM screen name Eighty6ChevyEric or email me at Eighty6ChevyEric@netscape.net
1986 Chevrolet Silverado Pickup