radio hook up - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Big Blue · 10-21-2019, 07:22 PM

This topic has been covered so many times, And I still can not find what I am looking for. I picked up a stock radio out of a 86 blazer. I even got the 3 plugs.
I got the speakers hooked up but on the third plug I have three wires coming out of it. A yellow,black, gray.
From what I have been reading is the black is ground, the gray is illumination.On some wiring diagrams it says the the ORANGE is constant power and Yellow is for switch power. I DO NOT HAVE A ORANGE WIRE on the plug.So what gives, need help please. Thanks John

ray_mcavoy · 10-21-2019, 08:02 PM

Yes, the black wire is ground, gray is illumination, and the yellow wire is switched power to the radio.

The constant power orange wire was only used on the factory radios with electronic tuning & digital display. And it was on a separate 2-wire plug along with a brown wire (connected to the parking/tail light circuit) used to signal the radio to dim the display when the lights were on.

Big Blue · 10-22-2019, 07:46 PM

Thanks ray_mcavoy, The reason I asked is that I am converting a pc power pack over the run the Radio. It says to connect the green and a Black off the big pin block. Use the yellow from the radio and a yellow from the big pin block to connect. I did this only to have the power pack shut off, only to go back on after I turn it back on. SO......That is why I asked about the wire.

Thanks Again, John

ray_mcavoy · 10-23-2019, 07:04 PM

You're welcome!

It sounds like you have things hooked up correctly. The fact that your PC power supply is shutting back off could be due to it's minimum load requirements. Many of them will turn back off if they don't have a minimum load on the +5V output. And since you're only using the power supply's +12V output (yellow wire) you aren't placing any load on the +5V output.

If that's the case, connecting a 10Ω, 10Watt power resistor between the +5V output (one of the red wires) and ground (one of the black wires) should draw enough current to keep the supply powered on. The resistor will get hot so mount it somewhere that won't cause any problems. Maybe even place it where the power supply's fan (if it has one) will be moving air across it.

10-21-2019, 07:22 PM	#1
Big Blue Registered User Join Date: Feb 2005 Location: Northeast--Bethlehem, Pennslyvania Posts: 642	radio hook up This topic has been covered so many times, And I still can not find what I am looking for. I picked up a stock radio out of a 86 blazer. I even got the 3 plugs. I got the speakers hooked up but on the third plug I have three wires coming out of it. A yellow,black, gray. From what I have been reading is the black is ground, the gray is illumination.On some wiring diagrams it says the the ORANGE is constant power and Yellow is for switch power. I DO NOT HAVE A ORANGE WIRE on the plug.So what gives, need help please. Thanks John __________________ Big Blue ( John ) 79 Chevy Pick up.....My Dailey STILL Working on a frame up: 1987 Truck body on a 78 Blazer frame. Need cab blasted to start project. Got the cab BLASTED, Now Prep and Paint. Started to lay SOME BONDO and primer. Done, Ordering paint. Got paint, Stuff painted,Cab,Fenders, Hood more later. 9/7/2015 Got the clear coat on,now time to take one off. Started to put things back (What a nightmare) like the heating and AC stuff,inside wire harness, outside AC unit and booster, still more. May 2016, still working on the inside. Got duck work in,heating and AC. Radio (stock) in dash with after market in console later, Speaker are hooked up, Steering column is in. Getting ready to drop the cab onto the frame, Working on engine now since I have the room. Well here it is 2018, got the engine in and it runs, now I need to get the exhaust system in so I can adjust the lifters, to loud right now. Got the exhaust on now I am waiting for the break parts to come in.

10-21-2019, 08:02 PM	#2
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,366	Re: radio hook up Yes, the black wire is ground, gray is illumination, and the yellow wire is switched power to the radio. The constant power orange wire was only used on the factory radios with electronic tuning & digital display. And it was on a separate 2-wire plug along with a brown wire (connected to the parking/tail light circuit) used to signal the radio to dim the display when the lights were on.

10-22-2019, 07:46 PM	#3
Big Blue Registered User Join Date: Feb 2005 Location: Northeast--Bethlehem, Pennslyvania Posts: 642	Re: radio hook up Thanks ray_mcavoy, The reason I asked is that I am converting a pc power pack over the run the Radio. It says to connect the green and a Black off the big pin block. Use the yellow from the radio and a yellow from the big pin block to connect. I did this only to have the power pack shut off, only to go back on after I turn it back on. SO......That is why I asked about the wire. Thanks Again, John __________________ Big Blue ( John ) 79 Chevy Pick up.....My Dailey STILL Working on a frame up: 1987 Truck body on a 78 Blazer frame. Need cab blasted to start project. Got the cab BLASTED, Now Prep and Paint. Started to lay SOME BONDO and primer. Done, Ordering paint. Got paint, Stuff painted,Cab,Fenders, Hood more later. 9/7/2015 Got the clear coat on,now time to take one off. Started to put things back (What a nightmare) like the heating and AC stuff,inside wire harness, outside AC unit and booster, still more. May 2016, still working on the inside. Got duck work in,heating and AC. Radio (stock) in dash with after market in console later, Speaker are hooked up, Steering column is in. Getting ready to drop the cab onto the frame, Working on engine now since I have the room. Well here it is 2018, got the engine in and it runs, now I need to get the exhaust system in so I can adjust the lifters, to loud right now. Got the exhaust on now I am waiting for the break parts to come in.

10-23-2019, 07:04 PM	#4
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,366	Re: radio hook up You're welcome! It sounds like you have things hooked up correctly. The fact that your PC power supply is shutting back off could be due to it's minimum load requirements. Many of them will turn back off if they don't have a minimum load on the +5V output. And since you're only using the power supply's +12V output (yellow wire) you aren't placing any load on the +5V output. If that's the case, connecting a 10Ω, 10Watt power resistor between the +5V output (one of the red wires) and ground (one of the black wires) should draw enough current to keep the supply powered on. The resistor will get hot so mount it somewhere that won't cause any problems. Maybe even place it where the power supply's fan (if it has one) will be moving air across it.



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