Help with old skool radio installation (77 308GTB)

THIS IS WHAT I WOULD TRY FIRST, IF YOU HAVE A SCREW GUN BATTERY YOU CAN QUIKLY TEST THE POSITIVES AND GROUNDS TO SEE WHAT DOES WHAT.

RED, POWER TO BATTERY

ORANGE, SWITCHED POWER TO KEY

BLUE, GROUND

GREEN, LEFT OR RIGHT SPEAKER +

GRAY, LEFT OR RIGHT SPEAKER +

BLACK, COMMON SPEAKER GROUND

 

ON NEWER RADIOS BLUE WIRES MEAN A SENDER WIRE, TO TURN ON POWER AMPS, ON THE ONE YOU HAVE I AM THINKING IT MAY BE POWER GROUND.

 

AND IF BLUE IS NOT GROUND, THEN YOU CAN RUN ANOTHER BLACK WIRE FROM RADIO CHASIS TO GROUND ON VEHICLE. AND LEAVE THE BLUE CAPPED OFF, UNLESS YOU NEED TO TURN SOMETHING ELSE ON, OR RAISE A POWER ANTENNA OR SOMETHING LIKE THAT.

 

I just found this on the internet- hope it helps-
Pioneer's non-EIA wiring colors

Black >> Ground
Red >> ACC
Orange >> BAT
Blue >> Power Antenna & Remote

Green >> LF+
Green/Black >> LF -
Gray >> RF+
Gray/Black >> RF-

Green/Red >> LR+
Black/Green >> LR-
Gray/Red >> RR+
Black/Gray >> RR-

 

On some older pioneers orange was the constant, not the red. Green is left positive, gray is right positive. The radio is "common ground" so all negatives get hooked to the black. If you have a multimeter you can check for continuity or resistance between the radio case and the blue wire. If not, go with the suggestion of attaching a wire to the case for ground, and cap off the blue wire.

 

IF I WALKED INTO IT NOT KNOWING, I WOULD FIRST GET POWER TO THE RADIO, THEN THE OTHER WIRES WILL BE SPEAKER WIRES, IN YOUR FIRST PIC YOU HAVE A CONNECTOR WITH THREE WIRES IN IT, THE BLACK GETS CONNECTED TO BOTH RIGHT AND LEFT SPEAKER GROUND, MOST TIMES ANYTHING WITH A BLACK STRIPE ON IT IS SPEAKER GROUND, THE OTHER IS HOT. WHEN YOU GET POWER WORKING, JUST TEST DIF WIRE CONNECTIONS ON SPEAKERS...........IT WONT HURT ANYTHING, UNTIL YOU GET IT RIGHT. I WOULD NOT HOOK EVERYTHING UP TO POWER ALL THE TIME, THE IF YOU LEAVE RADIO ON IT WILL KILL YOUR BATTERY.

 

You are going to have to do a little detective work here. The schematic does not match up to the radio wires you are showing on the back of the radio, so its going to require a a couple steps to get this narrowed down.

1. Does your car have a power antenna? If yes, does it go up when you turn on the key, even without the radio hooked up? According to the schematic, this should be the case.

2. Identify the wires you have in the dash of the car. You should have one ignition(+12v when the key is on), one ground(The one you show in the back of the pic with the spade terminal on it) And two pairs of speaker wires(R+,R-,L+,L-) You could also possibly have a 12v constant(always has power for retaining presets or clock memory. Judging by your pic and the factory schematic, this would be a wire someone added after the fact, not a factory wire.) Find the power wire first, and that should leave you four wires(speakers.) Once you verify that they dont carry any current, you can use a 9v battery to pop the speakers.(If you need a detailed explanation on how to do this let me know.)

 

COOL...............