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Want to test the orginal radio (AM/FM 8 track Delco ) to my car before reinstalling...when I bought car the owner had a modern radio in it and gave me the orginal....but said he didn't remember if it worked or not ...there was no wiring harnes on back so I ordered a set (3 piece) from form vendor....any idea on how to bench test...???
thanks
12 volts of FUSED power to what should be the YELLOW WIRE....the BLACK WIRE is a ground....and then an antenna. It is simple as that. You can get away with a 10 amp fuse in your 12 volts power supply.
The GRAY WIRE is for the light inside the radio when you turn your lights on.
TWO yellow wires, one is radio power, other is antenna.
Try either yellow wire to test it, but notice if the "stereo" light is on when the radio is OFF.
If so, that's the antenna wire, use the other yellow.
don't think these harness are correct then...that i bought as the wires seem to be diffrent colors....theres a white, black ,and blue plug each with four wires...but none of them have yellow wires....
Usually one yellow is for the station memory on modern radios. I never used mine ( before I pulled everything apart in the car) because it didn't have power to it. Now I have to go thru my boxes of stuff and see how to set the stations. Just out of curiosity.
This is what the colors are supposed to be.
This setup doesn't have power antenna lead, that would be another yellow wire in the spot below the present yellow wire. At least this pic will show you the CORRECT yellow for radio power.
The other two plugs are speaker wires.
Each speaker lead is paired side by side. Second plug is front, bottom plug is rear.
I suggest you install your aftermarket plugs and compare colors to pic and tag your wires with correct color it should be.
When you start hooking up speakers it will help.
Great discussion thread...I need to do this for my Pace Car as well but haven't tackled it. I did this graphic using PowerPoint, using Kaps image so I can remember the wire color codes. Feel free to add, delete or comment and I'll repost. In fact, I'll grab a photo later of the radio (8 track) with power antenna and add to the mix.
So What do you make of this. It is plug wires from a Pace Car 8 Track. I pulled it to send off for repair to the 8 track because it did not work...and it still sits on a shelf.
I see no yellow wire for the power antenna...that was an incorrect aftermarket device. The radio light wire (gray) connects to the middle plug.
That grey is correct, a speaker wire. In my pic the grey does look a bit off, and the tan looks orange, but my color schematic(in my 79 shop manual) does verify grey.
Don't know what to make of you missing the grey light and yellow antenna wires in the top plug but I do see a bunch of aftermarket connectors in your pic.
Just to verify speaker wires.....
LH front, tan and grey.
RH front, dark green and light green.
LH rear, yellow and brown.
RH rear, dark blue and light blue.
I don't see your yellow and brown LH rear wires.....
Just occurred to me, does an 8 track radio even use a light in the radio as the "dial" is in the flip door? I've never paid attention to my pace car 8 track while both my 79s have cassettes and ARE lighted.
And is that your original radio and harness or did it come from another car without a power antenna?
Are the pushbuttons black or chrome?
That grey is correct, a speaker wire. In my pic the grey does look a bit off, and the tan looks orange, but my color schematic(in my 79 shop manual) does verify grey.
Don't know what to make of you missing the grey light and yellow antenna wires in the top plug but I do see a bunch of aftermarket connectors in your pic.
I don't see your yellow and brown LH rear wires.....
Curious if you would pick up on the aftermarket connectors. Well, I dug around under the console and apparently, for some unknown reason that many of us have experienced, the connectors and wires were cut from the harness and then reattached. The yellow and brown are there and have aftermarket speaker wire attached to them but are not routed through the radio. I am sure the previous owner had a rationale and I suspect if I dig some more I'll find them wired into RH speaker....but then I would not count on that either.
And then there is the aftermarket power antenna. As I dig around, I find the yellow wire (photo) and trace it back to the power antenna relay. But is lay bare on the surface of the tunnel still taped to its companion orange wire.
It seems as tho the metal clips in the plastic connector are missing or removed and therefore a previous owner did a work around.
And is that your original radio and harness or did it come from another car without a power antenna? Are the pushbuttons black or chrome?
Yes...original 8 track radio and the model # (GM#) falls in the range of a 78. I also have a 79 8 track with a higher GM#. The pushbuttons are packed away but believe they are chrome. The buildsheet and window sticker call out RPO UM2 - AM/FM 8 track.
I'll be in Carlisle next week and will look for some radio harness with plugs and work me up a bench test radio operation with speakers. I'll also look for those pins that go inside the connector.
Last edited by hunt4cleanair; Aug 20, 2015 at 03:36 AM.
If it matters to you the correct Corvette pushbuttons are black.
I too had to correct wiring in my white79 as past owner had installed an aftermarket radio. Found radio pigtails on ebay for like $7. My install was a little easier as it has no rear speakers.
I did wire my front left speaker to the left rear spot in the harness, kinda gave me some balance control left to right that the factory radio doesn't have(they just have fader front to rear).
Just occurred to me, does an 8 track radio even use a light in the radio as the "dial" is in the flip door? I've never paid attention to my pace car 8 track while both my 79s have cassettes and ARE lighted.
Yeah...never paid attention to it. And how many ops have I done on 78s?
And is that your original radio and harness or did it come from another car without a power antenna?
Just to be clear, your photo in #7 is a 79 AM/FM radio. There may be changes in 79 from 78.
Where is the source for the gray radio light wire? Light switch from dash? I see in my photoa and connector, gray wire missing but I see it on the schematic.
So, the yellow power wire for power antenna uses the empty connector position on the top plug?
Last edited by hunt4cleanair; Aug 20, 2015 at 04:13 AM.
My photo, post 7 is from a 79, but not a corvette. Didn't think that would present any problems, altho the tan and grey wires do look off a bit.
Figured if nothing else, process of elimination would get everything hooked up.
Schematic says grey light wire comes from inst. panel switch, but it probably ties in somewhere along the way, not actually at the switch.
Perhaps you could tie it in on the heater control overhead spot light wire?
In my photo, the yellow antenna lead goes in that empty spot in the top plug under the other yellow wire. I believe later C3s used a pink wire for the antenna.
So I got thinking and remembered I had squirreled away a Pace Car dash harness, unmolested, so I retrieved it this afternoon and sure enough, there are the "correct" radio plugs with color coded wires that trace back to speaker connectors and onto power antenna relay...accompanied with the orange wire. I had used it before to trace anti-theft alarm, horn relay, etc and I had those connections tagged.
This photo shows the power antenna "yellow" wire.
Last edited by hunt4cleanair; Aug 21, 2015 at 03:24 PM.
If it matters to you the correct Corvette pushbuttons are black.
I too had to correct wiring in my white79 as past owner had installed an aftermarket radio. Found radio pigtails on ebay for like $7. My install was a little easier as it has no rear speakers.
I did wire my front left speaker to the left rear spot in the harness, kinda gave me some balance control left to right that the factory radio doesn't have(they just have fader front to rear).
KapsSA is definitely correct about the 1978 AM/FM push buttons being black....(including CB option). I've looked at a LOT of pix of OEM 1978 cars for sale with very low miles (including the Pace Car) in order to determine if the buttons were chrome or black. I am 99% sure they are black....so I purchased an AM/FM/CB in great condition to restore original options.
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How do you bench test a orginal 1978 radio
