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Discussion Starter · #1 ·
I just bought an 06 trailblazer for my wife. The radio was jacked so I purchased a new one. I work with electricity so I decided to install it myself. I got some beer, called a friend and went to town. I soon discoverd the ACC wire only puts out 4V and I needed more to turn my radio on. My buddy has on 03 silverado with an aftermarket unit so we took his truck apart and figured out where his ACC tapped into (white wire under the stearing column). We found the same wire on my truck and took a reading, the wire read 12V with my car in ACC and 0V with it off. Happily I put the radio in the trailblazer. The radio works like a champ until I put the truck in drive... then it shuts off. I took another reading and found out that when you press the button to take the vehcile out of park the voltage on the wire goes to zero. Does anyone know what wire I need to tap the ACC wire into? Thanks for the help
 

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2002 gmc envoy_sle
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go buy the proper wiring harness and stop tapping into wires in which you have no clue what they do. Our wiring harness is not going to be the same as your buddies '03 silverado
 

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2006 chevy trailblazer_lt
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Reading just about ANY other post about car audio on here, someone ends up mentioning that the radio on these doesn't turn on with voltage from the accessory wire, instead it is Woken up via Class II Data transmission from the BCM. (The Car's Computer tells the radio to turn on)

i'm going to assume since u provided almost no information that your putting an aftermarket radio in?

Depending on Whether your Trailblazer Has the BOSE system or not you will need one of 2 adapters for easiest install, there are many others but these 2 come to the top of my head. Hopefully the aftermarket radio you picked out has 2 sets of RCA Pre-Outs (front and back)

Non Bose- METRA GMOS-01
BOSE/Amplified- METRA GMOS-04

these will keep your door chimes, Onstar, and provide the Class II Data component to make the aftermarket radio speak the same language as the rest of the TB. Being good with electricity, and being able to install a car stereo properly are 2 different things, anyone can read a multimeter.
 

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2006 chevy trailblazer_lt
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might as well save you another question and tell you that if you have steering wheel controls (don't know if you have a base LS or LT or what because you didnt fill in your user information) they will not work with the aftermarket radio. PAC makes a few steering wheel control modules that correspond to the make of aftermarket headunit.

for my Pioneer i used the SWI-PS (For Sony and Pioneer Headunits)

Things don't work just because you plug them in. a lot more goes into electronics than the electrical connection.
 

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2003 trailblazer_lt
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I just wanted to say thank you to MAY03LT for not being a ****. I don't know what the switched power wire is so I don't know if that is what I was looking for.
this thread will prob get the curtain, if you want to go back to the original thread or take this to private messaging it's cool, Im sure we can get the radio working:tiphat
 

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2002 gmc envoy_slt
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I just wanted to say thank you to MAY03LT for not being a ****. I don't know what the switched power wire is so I don't know if that is what I was looking for.
no love for MAY03LT ?
 

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Discussion Starter · #8 ·
what is the switched power wire?

Basically my situation is that I have a radio installed that won't work because my acc power is low. I now know that I can buy one of two products that will produce 12v. GMRC-01 or XSVI-2003. Axxessinterface.com is how you find that stuff out if you didn't know that already. However I have already cut off the old harness and thrown it away (because I thought the radio worked) so I would either have to buy a new harness from chevy and wire that back on... or find out which wires are which and cut off the harness from the new power supply and wire that in. I was hoping there would be an easier way to fix the problem... What would you suggest?
 

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what is the switched power wire?

What would you suggest?

The switched power wire is the one that switches to B+ when the ignition switch is in the ACC and Run positions. This wire is not in the head unit wire harness (unlike the 97% of cars that do), but there is one in the truck that can be used.

For now, I would rewire the switched B+ (RED wire for the head unit) so at least you have tunes.

Feel free to send me a pm for detailed instructions for accessing and tapping the circuit.
 

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2005 gmc envoy_slt
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Thank you...

Thank you meb885 for the links to Crutchfield. I wanted to swap my Pioneer in the Envoy eventually but knowing about these parts makes me want to do it now, haha. :cool:
 

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2004 chevy trailblazer_ls
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However I have already cut off the old harness and thrown it away (because I thought the radio worked) so I would either have to buy a new harness from chevy and wire that back on... or find out which wires are which and cut off the harness from the new power supply and wire that in. I was hoping there would be an easier way to fix the problem... What would you suggest?
Metra makes a replacement harness for this type situation part number: 71-2003-1.
http://www.metraonline.com/fit.aspx

I remember years ago that sometimes when your acc. power was low/no power it was a weak fuse or one was blown. Don't think it's like that anymore, but I could be wrong.
 
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