I bought an 8 track & a correct am/fm stereo (w/multiplexer) for my '70 Cutlass. The wiring harness is long gone as a aftermarket radio was installed. The Stereo unit has a 3 pin connector that accepts the 3 prong connector from the 8 track unit. The other wiring harnesses coming off the 8 track is a 3 prong w/ yellow-blue/yellow/black - black. I assume the yellow is 12v and the black is ground, is that correct? The middle one, what does that hook up to? Then there are two other wires coming off the 8 track, a male connector blue/white wire and a female connector w/ blue/red wire. I assume they conect to the speakers. I know this is probably simple but I do not want to do it incorrectly and destroy my new units. Thanks for the help!

 

When correct, you have a 3 pin plug coming from the front speaker but only two wires. That will plug into the 8 Track player and then the yellow wire from your dash harness will plug into the bare spot of the 3 pin plug. Then the 8 Track player will plug into the radio. With an 8 track player and Stereo unit, you would have a rear speaker. That will hook to the single wire from the 8 track and then the other single wire will go to the single wire on the passenger side of the radio. The rear speaker grounds at the speaker.

 

Makes sense, the two wires are front speaker wires and the other yellow is the hot wire to connect to 12v. I do not see a ground wire then, is it self grounding? I would like to bench test the unit, just hook up power to the yellow wire and ground the unit? THANKS for you help

 

Yes, the case is ground. The dash has a ground strap that goes around the back side of the volume hole. When it is bolted in the car it grounds through this strap. The strap stays on the dash and you would not know it is there if you did not look for it.

 

Here is a picture of the ground strap on the back side

 

Please don't tell you wife but I think I love you!! Thanks a million!

 

Yes, the light blue wire in the three pin plug is the front speaker wire. Yellow is 12vdc. The black wires in the harness are ground. The dark blue wires are rear speaker wires. The 8 track player should also have a braided ground strap(when installed in the car) that goes from that metal tab on the chrome face of the player to the threaded stud on the passenger side mounting bracket.
I have braided ground straps and drive belts if you need them.

*****************BENCH TESTING***************

If your plugs are still intact, this will be easy.

(When referring to male or female plugs, I mean the plastic part. Not the electrical connector.)

The three wires in the three pin female plug, a couple ground wires and the dark blue wire w/red stripe are all you need to hook up in order to bench test the player. It can be played by itself with out the radio involved.

In the three pin plug on the 8 track, the yellow wire is 12vdc, the black wire is ground and the center light blue wire is the front speaker wire.

The dark blue wire w/red stripe (male plug) is the rear speaker wire.

You’ll need to run a ground wire from the battery/power supply to the 8 track player’s chassis and the speaker or speakers.

ALWAYS use a power supply with a circuit breaker or put a 10 amp inline fuse in the power line from a car battery if bench testing with a car battery.

****************Installation in the car*************

The 8 track gets installed in line with or in between the car and the radio. To install the 8 track, unplug the male three pin plug from the radio and plug that into the three pin female plug on the 8 track. Then plug the three pin male plug from the 8 track into the radio. If your radio is a stereo unit or has the rear seat speaker option, plug the wire coming from the side of your radio(dark blue wire w/female plug) into the dark blue w/red stripe wire (male plug) from the 8 track. Then plug the dark blue w/white stripe wire (female plug) from the 8 track into the male plug from the rear seat speaker.

 

Very good news guys. After bench testing both units they work! The sound was not as robust as I would have liked but everything was hooked up with alligator wires, hopefully with correct connections the sound will be a bit louder, thanks for your help!

 

Glad to hear it. If they have been sitting a very long time, they may actually get a little louder after they run for a while. Not much but a little. If the voltage you had when bench testing was low (less than 12vdc) it may also have affected them. They should have a good 14vdc.
Could also have been the speakers themselves. If they aren't housed/enclosed, they won't sound right.`
You also want to make sure that you are using 8ohm speakers. Most modern speakers are 4 ohm and some really new stuff appears to be 2ohm. Using 4 or 2 ohm speakers will actually make it sound louder but you are over driving your amplifiers in the 8 track and could burn them up.