How to wire and speaker? '72 T'All

ojh

Member
I have the dash apart fixing the hvac controls and I see somebody has done some creative wireing to the radio - this is a customers' truck, I don't think the radio worked.
I am ready to reassemble the dash but I'd like to correct the radio wireing, I have the factory manuals and they don't show a radio - probably an unecessary luxery in thier opinions, they do provide a circuit number for one but the dwg for the radio supply and the speaker are not there.
The radio has a 3gang connector, brown, green and black wires. What goes to what? I presume common black for radio and speaker?, then the radio needs +12v and the speaker needs a supply. I think radio gets green and speaker gets brown, but there is no indication and the existing wireing is questionable.
Thanks, oj
 
As you correctly indicate, the factory diagrams do not show the radio or call out the speaker wiring. Circuit 86 is the power supply from ig sw to fuse panel. Perhaps the head unit receives chassis ground from the dash mount. I would assume one wire of the radio gang plug provides fused power supply to the device, with the remaining two providing pos and neg output to the speaker. Which is which...idk. Most folks who give a care about tunes in the truck go with an aftermarket head unit and door speakers, rendering the factory circuitry minus power supply as useless.
 
Black to 4 amp fuse switched power (off with key off, on when key on), other two wires go to speaker, green positive speaker terminal, brown negative speaker terminal

the radios chassis is ground, it should have a ground strap on the back.
 
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