Wire for radio

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I'm installing a slidebad radio and it needs a key on, constant, and ground. In my radio area I have one plug that I cant figure out. the two combined purple/white seem to be a key-on. the blue/red has 1ohm resistance to ground so I don't know what that is or if this plug it for the radio? Any help would be appreciated.



 
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See page 5

https://www.7173mustangs.com/images/1973_full.pdf

I'm not great at reading wiring diagrams, but it looks as if the light blue with red is back lighting maybe?? (IE comes on with lights)
I checked for voltage and light blue with red comes on with light switch. I don't need that I guess. Before I hack up the plug I was hoping to make sure is is meant for the radio. Anyone else know for sure?

Also, I need a constant. Take it off the fuse block I guess?

 

midlife

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Yes, that plug is ACC power (white/purple) and lamps (blue/red). Another good place to tap into battery power is the circuit breaker for your e-flasher and brake switch, or splice into the cigarette lighter (blue/white).

 
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That is the connector for the radio power and light. The white/purple stripe wire is key on and runs through a 15 amp fuse in the fuse block that it shares with the emergency flashers, back up lights, and wipers. The light blue/red stripe wires are used for all dash lights that are dimmable.

 
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Ok, possibly dumb question about this.  The two purple/white wires that are for accessory power.  One provides power and the other completes the circuit to ground?  If yes, which is which?  Let me know.

Thanks!

Scott

 

midlife

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Ok, possibly dumb question about this.  The two purple/white wires that are for accessory power.  One provides power and the other completes the circuit to ground?  If yes, which is which?  Let me know.

Thanks!

Scott
That's a negatory.  The other wire (blue/red) is lamp power for the radio.

 
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I guess I'm wondering if both of the purple and white are hot leads, why are there two of them? That seems redundant. I'm sure there is a perfectly logical explanation that is eluding me here. The other question though was, if both the purple and white are hot, does it matter which one I use?

 

midlife

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I guess I'm wondering if both of the purple and white are hot leads, why are there two of them?  That seems redundant.  I'm sure there is a perfectly logical explanation that is eluding me here.  The other question though was, if both the purple and white are hot, does it matter which one I use?
Yes, both are hot (fused) leads.  Why are there two of them?  As I tried to explain, there are a number of devices chained together, so there has to be a wire coming from the first unit going to the unit in question and a second wire returning from the unit in question to a third unit.  If you use only one of the wires, and ignore the second wire by leaving it hanging, there will be other units that will not get voltage.

 

midlife

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Yes. Both wires need to be on the same side of the splice.

 
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