My car is a 78 Pace Car. I know some of the questions sound dumb but I want to make sure I do them right.

I have a Pioneer DEH-P5900IB head unit and I am not using any amps. The speaker wiring is no plobem. Here are the areas I need help. On the Pioneer wiring harness.

1. Yellow connects to a constant 12v supply. I assume this goes directly to the battery?

2. Red is connected to a terminal controlled by the ignition switch. THis I assume is for the accessory on the ignition. What would be the color of this wire on the origional GM wiring harnass?

3. Orange/white connects to a lighting switch terminal. Once again what would be the color or correct wire to splice into on the factory harness.

4. Black is the chassis ground, any good suggestions on where to connect this one?

5. blue/white is for power amp or auto antenna. I do have a power antenna that I could switch off and on with the power of the factory head unit, so what would be the correct wire for this?

6. Is there anything that I have to connect to the negative terminal of the battery?

Thanks for any help!

 

On the Stereo:

Pioneer Yellow Constant 12 Volt Source

Corvette Wiring differs on the radio connector. Best bet is to run directly to the positive (+) side of the battery (Hint) go to Radio Shack or any electronic supply store and purchase a 1-1.5 inch round magnet with a hole in the center. somewhere between the radio and the battery, wrap the wire around the magnet about 5-8 turns. This will greatly cut down on noise.

Pioneer Red Switched 12 Volt Source

Corvette Wiring Color = Yellow

Pioneer Orange/White Lighting Dimmer Control

Corvette Color = Gray Wire At OEM Radio or any orange wire going to a instrument light.

Caution: GM cars are sometimes different around 70-81 Double check these color codes with a meter or test light. Example; Some Camaros use the Gray as a constant 12 volt and the Yellow as the dimmer.

Black needs to go on a GOOD CLEAN GROUND. The best method is to use a small bolt & nut drilled thru a support under the console.

Pioneer Blue Wire Power Antenna Trigger

Corvette Wire = Dark Green (Also Check This one varies with GM cars)

One Last Note: Invest in a High Quality Noise suppressor. You can pick up one online or at a car audio or auto parts store. Again, GM cars are noted for awful sine wave noise from the charging system.

Hope this helps...

ADDITIONAL NOTE: Make sure the connections are all tight. FYI: Many Car Audio suppliers offer "Plug In" adapters that will save you time and headache. If your OEM wiring harness is intact, this is the way I would go. http://www.tune-town.com/Cars/stuff/...t_Corvette.htm The best $10.00 you will ever spend.. We use these on all installations.

 

Thanks for the help, I did buy a haness but could not make it wor? It came with an additional connection for the yellow and orange but there was noting under the dash to connect that plug to? I will try and run those connectins and see what happens.

 

In your factory harness you can use the three wires originally used for the radio or you can make your own connections. You want the head unit power and ground to be on the same relative circuit so you don't get a ground loop and pick up RFI.

Just test the wires to make sure you have a good solid 12V constant, a switched source, and a good ground.

 

Don't want to sound stupid but in simple English what does this mean? "You want the head unit power and ground to be on the same relative circuit so you don't get a ground loop and pick up RFI"

In the power part of the harness I have 2 yellow, 1 black and 1 gray wire. Cant the ground be spliced to this black wire?

I have made a constant power lead and was going to use that and ground to a support bracket. I still see no wire that would be green for the antenna. Could that be the gray one?

In the factory harness there are 3 plugs. 2 are for speakers which are easy enough and the last one I assume is the power both constant and switched and the power antenna connection since all these things worked on the factory unit. But when I wired it the first time nothing happens?

 

Just saying, if you are using the 12V constant from the original harness, make sure you use the ground from the same harness. If you run a power wire from the fuse panel, run your ground to the same part of the chassis the fuse panel grounds to.

The reason is you don't want a loop. say you power the head unit off of the battery but ground it to the birdcage. You're creating a large loop, and that acts like a net for picking up interference. RFI is just Radio Frequency Interference. Modern head units are a lot more susceptible to picking this stuff up, and it comes out amplified more than it used to when people didn't notice it.

 

It works I have power and music finally that old crappy 30 yr old blown speaker sound is gone! Now I just have to get it all back together!

Thanks for the help!