04 chevy express 3500 radio switched 12volts new radio install.
I've sliced into the oem radio harness' red w/ white tracer for constant 12VDC an the Black for ground. which color wire is the switched 12VDC?
I saw on y-tube a man splicing into the climate control leftist beige wire. I'd prefer to steal from the radio harness.

my new radio has ulimation organe w/ white tracer for dimming the backlight, the express has like 3 organe wires how do I know which to connect to I'd prefer to not trail an error it.


thanks

 

electrical schematics are available on charm.li

 

wow thats a wealth of infor. thanks mountainmanjoe for the link I've saved it definitily can use on other GM stuff.

I navigated though all of it an didn't find or didn't understand how to find. apparently I need to get into power distribution.
here's where I navigated to.in connection ID didn't see the red power wire, or the switched 12VDC I need.

 

The stereo doesn't have ignition switched 12V.
It gets woken up by special message on the class 2 serial data communication network.

 

will steal from the ac/heat blower here
thanks mountainmanjoe will report back w/ new audio sys.

 

hopefully you don't overload that circuit

 

ok I'm not taking the chance on over loading the blower
plan B was to look inside the fuse block under driver seat which requires removing the whole dam seat.
plan C connect though the firewall to the battery idolater which mite ruin the isolator. I do see a rubber gromit on driver firewall near parking brake but it's tight from uptop maybe accessible from underneath.
plan D use the same constant 12VDC from radio an branch off it w/ my own manual switch.

 

the seat is just 4 nuts. No biggy.


instead of a switch, use a relay energized by the HVAC

 

I've never connected a relay I know it has 4 posts this mite be a tad to conplicated for me.

don't want to mess w/ removing the seat. leaning toward plan D
plan D use the same constant 12VDC from radio an branch off it w/ my own manual switch

 

except the one day you'll forget to switch it off and get stranded in the middle of nowhere