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Radio wiring

96K views 10 replies 3 participants last post by  kirby2 
#1 ·
Hello -- I replaced factory radio in a 2002 Silverado with aftermarket unit (the factory radio connector had been removed). The wiring harness includes three dark green wires (solid green, no stripe): one is 12V+ (switched by ignition), one is for a speaker, but I'm not sure what the third one is for. All the wiring diagrams I've seen show only two dk. green wires going to the radio.

The harness also has a fourth dark-green wire, but that one has a white stripe, and I believe it is the vehicle speed signal (for the speed-adjusted volume feature probably). I've seen diagrams showing some Silverados having a dk. green "E&C" wire which may be some kind of diagnostic.

Does anyone know what the third solid green wire is for and if it needs to be grounded or just taped off? Thanks.
 
#4 ·
Thanks Machster69. GM-UPFitters website is great but, unless I looked in the wrong place, it seems to have electrical schematics only back to MY2003. I think the electrical system was extensively upgraded starting in '03, so the 2003 schematics won't work for my '02 truck.
 
#6 ·
Heres what you need to make the stereo work, all other unused wires should be taped off.

Radio 12v orange + radio harness
Radio Ground black - radio harness
Radio Ignition dk. green + radio harness
Radio Illumination brown + radio harness
Factory Amp Turn-on orange + radio harness
Notes: The amplifier is behind the glove box.
Power Antenna N/A
LF Speaker +/- tan - gray +,- radio harness
RF Speaker +/- lt. green - dk. green +,- radio harness
LR Speaker +/- brown - yellow +,- radio harness
RR Speaker +/- dk. blue - lt. blue +,- radio harness
 
#7 ·
OK -- my radio harness has only one orange wire, so the amp turn-on may be the answer for the extra wire -- also, I wasn't aware there might be an external amplifier behind the glovebox. I'll check that. Thanks much Damion! and machster69 too.
 
#11 ·
Sorry for the delay Machster69 -- believe it or not, after several months since my initial post, I only recently got the aftermarket radio working (I wasn't driving the truck a whole lot, so it wasn't essential.) Turns out there was a loose connnection elsewhere (behind the instrument cluster) that was preventing the radio from working. But it's all operating fine now.

As for the color coding of the radio wiring on the 2002 Silverado 1500, Damion's posted reply was essentially correct. My truck doesn't have a factory amp, so my harness has only one orange wire (which is the constant 12V+). And it has no power antenna either.

After connecting the constant 12V, the switched 12V (ignition), the ground wire, the illumination wire, and the eight speaker wires (4 sets), there were three unused wires in the factory harness that I taped off: one light gray (dimmer wire), one dark green (probably the vehicle speed signal (VSS) for the speed-sensitive volume on the factory radio), and one dark-green-white-stripe (unknown, but possibly the 'E&C' wire according to some diagrams I've seen).

FYI, I found that using a flashlight battery to identify speaker wires by "popping" each speaker was helpful. The battery makes a mild static noise in the speaker when connected to the corresponding wires. This made it easy to match the speaker wires in the vehicle harness to the aftermarket radio harness.
 
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