i recently bought a 79 chevy and i have no clue as to how to wire a stereo in the dash considering that there is no existing wiring harness. any ideas or thoughts would be helpful.
get your constand and switched 12 volts from the ignition harness, and run your own speaker lines
Run a wire from your battery, fused that's the B+ (yellow) be sure it's from the positive terminal.
Ground the HU to the firewall or floor, whichever is closer.
turn the car on, test for voltages on the wires, there should be at least two, use the one that comes on with the key (ACC) red wire, tape the others up, you won't need them.
Now, you have all wires with no power on them, if you have the patience, check each pair and find your speakers. (don't short the wires on th HU)
you can also run a new pair to all four speakers, if you have that one speaker in the dash....unplug it, it won't work with your new radio.
After this, you're all done, don't forget the antenna cable..
Those are my suggestions, do a search and find out what wiring to use and how to make proper grounds. Should be an easy install.
be certain that there are no ground wires or postive wires in your way if you do the 'speaker test'
you can find the speaker pairs by testing resistance through the pairs, should be anything like 3.2-7.4 ohms...just something. This may save you a little time, put your live speaker outputs on it to see where it is, if it's the corresponding leads, connect them and use another pair to keep testing the speaker wires.
I'm willing to bet you will need new speakers too, that's an old car.
Listen to these guys, They're giving you good info. The old cars are funny. When I first installed a car stereo and speakers was @1980. I had a 72 Ford Pinto that had an am radio and the one dash speaker. Of course at that time Sparkomatic, Kraco, Jensen. Those brands were easy to obtain. I had a Casette player with no auto-reverse. I had to power it from the radio fuse in the fuse block and run speaker wires all over the car. There was no 4 channel radios so you hooked all the speakers together off of the one negative and two positive speaker wires from the radio. I put 6.5's in both doors and (3) 6 x 9's in the rear deck . It was a lot of cutting. These were hooked off a sparkomatic eq/booster. Very primitive but it worked. With the knowledge on this forum you shouldn't have a problem with your install. Running the speaker wires will be a pain. Especially through the doors if you are adding door speakers.
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Harv
make sure you got the polarity right when you find the correct speaker wire pairs by doing what flynntech mentioned. use a small battery and just hook up your speaker wires to it and once you hear a small pop, you got it hooked up right.
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always looking for new info and willing to give it