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2007 chevy trailblazer_ss_1ss
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2,006 Posts
Discussion Starter #1
All,

well this is my second shot at trying to ask for some advice. I went on that tbssowners site and they all pretty much bagged on me and had no intent on trying to pass advice or help me out :suicide:.

But i have an '07 TBSS 2WD and i have an air/fuel lean rich gauge that i am putting where the SS emblem is next to the radio. Its not any kind of performance monitoring or anything like that, its purely cosmetic effect... my brother had one of the gauges in his GP (grand prix) GXP and i loved it... plus it is something inexpensive and i think looks good....

but the problem is the TBSS has 4 O2 Sensors and for the gauge to function you need to tap into one of the O2 Sensors signal wire. Does anyone know which O2 to tap into? and what wire is the signal wire...On my brothers GP GXP the O2 sensor had a purple wire that tied directly to the purple wire off of the gauge... i wish the TBSS was that easy :hissy:

but any help is greatly appreciated and hopefully more helpful then the other people on that other site....
 

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2003 chevy trailblazer_ls
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1,708 Posts
Not knowing how many wires you have on your O2 sensors I would guess that the black is ground, white is power (heated O2 sensor) and grey is signal. To make sure put a digital VOM meter on each wire while engine is running and when you goose the engine the signal wire will jump or dive in voltage. 0-1.8 or something like that. One wire should stay at 0 and one should stay at 12v or so.
 

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2007 chevy trailblazer_lt
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912 Posts
Thanks for the advice guys! Finally, somewhere to start!

Another thing.....if we go poking around at o2 sensor wires, will that do any damage? Like, if we used the wrong wire and had to switch wires, or if we had to otherwise remove the gauge, will it cause any problems? Codes, rough idle, etc...
 

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2003 trailblazer_lt
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9,856 Posts
You shouldn't have any problems, of course if the 02 wire gets cut or the new wire touches ground with the key on, a code could be set

here are the rest of the wires

Bank 1 upstream low sig (from pcm) tan
Bank 1 upstream high sig (from o2) purple/white
Bank 1 upstream Heater B+ pink
Bank 1 upstream Control black/ white

Bank 1 downstream low sig (from pcm) tan/white
Bank 1 downstream high sig (from o2) purple/white
Bank 1 downstream Heater B+ pink
Bank 1 downstream Control brown

Bank 2 upstream low sig (from pcm) tan
Bank 2 upstream high sig (from o2) purple
Bank 2 upstream Heater B+ pink
Bank 2 upstream Control light green

Bank 2 downstream low sig (from pcm) tan
Bank 2 downstream high sig (from o2) purple
Bank 2 downstream Heater B+ pink
Bank 2 downstream Control red/white
 

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2007 chevy trailblazer_ss_1ss
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2,006 Posts
Discussion Starter #8
You shouldn't have any problems, of course if the 02 wire gets cut or the new wire touches ground with the key on, a code could be set

here are the rest of the wires

Bank 1 upstream low sig (from pcm) tan
Bank 1 upstream high sig (from o2) purple/white
Bank 1 upstream Heater B+ pink
Bank 1 upstream Control black/ white

Bank 1 downstream low sig (from pcm) tan/white
Bank 1 downstream high sig (from o2) purple/white
Bank 1 downstream Heater B+ pink
Bank 1 downstream Control brown

Bank 2 upstream low sig (from pcm) tan
Bank 2 upstream high sig (from o2) purple
Bank 2 upstream Heater B+ pink
Bank 2 upstream Control light green

Bank 2 downstream low sig (from pcm) tan
Bank 2 downstream high sig (from o2) purple
Bank 2 downstream Heater B+ pink
Bank 2 downstream Control red/white
thx MAY03... much help.. i went to the dealer and they brought up the schematics on there computer system.. was like reading giberous sp?... but i thought it would be bank 1 upstream.. just didnt know if it was the purple/white wire or the tan since both are signal.. i also talked to autometer and they wanted me to tap directly from the pcm?? doesnt ring a bell for me.. so im gonna shoot for the purple/whie wire... lets see what happens :worried:
 

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2003 trailblazer_lt
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9,856 Posts
thx MAY03... much help.. i went to the dealer and they brought up the schematics on there computer system.. was like reading giberous sp?... but i thought it would be bank 1 upstream.. just didnt know if it was the purple/white wire or the tan since both are signal.. i also talked to autometer and they wanted me to tap directly from the pcm?? doesnt ring a bell for me.. so im gonna shoot for the purple/whie wire... lets see what happens :worried:
no prob man....for each sensor, every wire except the heater B+ goes to the pcm, they prob want people to avoid tapping at the sensor to avoid the possibility of the wire hitting the exhaust (which would send the signal to ground and cause problems)

I don't know how hard it is to access the pcm in the SS but if you decide to do it that way let me know:cool:

oh yeah that schematic wasn't THAT bad:D
 

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2007 chevy trailblazer_ss_1ss
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Discussion Starter #10
no prob man....for each sensor, every wire except the heater B+ goes to the pcm, they prob want people to avoid tapping at the sensor to avoid the possibility of the wire hitting the exhaust (which would send the signal to ground and cause problems)

I don't know how hard it is to access the pcm in the SS but if you decide to do it that way let me know:cool:

oh yeah that schematic wasn't THAT bad:D

i wasnt baggin on your schematic diagram.. i was talkin bout the one at the dealership.. they sat me at the computer like i knew what i was readin lol.. thats what i meant.. but i got the gauge and as soon as it warms up ill install it and put up some pix... i have a 4 pc. billet grille and my billet bowtie emblems... im gettin her ready for a dyno run in april... lol my baby gotta shine!!!! lol.. thx for all the help...
 

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2003 trailblazer_lt
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9,856 Posts
i wasnt baggin on your schematic diagram.. i was talkin bout the one at the dealership.. they sat me at the computer like i knew what i was readin lol.. thats what i meant.. but i got the gauge and as soon as it warms up ill install it and put up some pix... i have a 4 pc. billet grille and my billet bowtie emblems... im gettin her ready for a dyno run in april... lol my baby gotta shine!!!! lol.. thx for all the help...
it's all good, I read diagrams on a daily basis so none are "that bad":laugh:

let me know how you make out:cool:
 
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