Trailblazer SS Shifter TC Button Question

Daniel644

Well-Known Member
on the Trailblazer SS shifter it has a 2 wire traction control button, is that button a momentary switch or a toggle switch? I've swapped in an SS shifter into a vehicle that doesn't have traction control and after recent youtube videos from Chris Fix and Jays2cents i'm thinking of possibly re-purposing that button into a kill switch or maybe even a push button starter, but I need to know the type of switch to then figure out how to best use it.
 

Blckshdw

Moderator
:biggrin: I did the same thing, for the same reason. The button is momentary, not latching/toggle, so you'd need to design your circuit around that.

I was originally going to use it as a kill switch for the auto feature for my power folding mirrors, but the motors died. :hissyfit:
 
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Daniel644

Daniel644

Well-Known Member
:biggrin: I did the same thing, for the same reason. The button is momentary, not latching/toggle, so you'd need to design your circuit around that.

I was originally going to use it as a kill switch for the auto feature for my power folding mirrors, but the motors died. :hissyfit:
OK then being a momentary I'm thinking using it in conjunction with the starter relay (need to dig into some wiring diagrams), so the idea is like a push button start, you put the key in the On position then reach down to the shifter and hit the button to crank the car and breaking the circuit in such a way that the key being turned to the crank position would do nothing. so effectively a hidden push button start, that seams the best way to go about for a momentary switch.

what would be the best way to go about that?
 

Blckshdw

Moderator
:undecided: That's a cool idea. You could de-pin the ignition switch harness, where the starter trigger wire is, extend a wire that's tapped into the run position wire, run that to the shifter button, and then back to the starter trigger wire. This way the key has to be in the run position, or the push button starter won't fire. And since the starter trigger isn't connected to the ignition switch, turning the key all the way forward won't do anything.
 
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Daniel644

Daniel644

Well-Known Member
:undecided: That's a cool idea. You could de-pin the ignition switch harness, where the starter trigger wire is, extend a wire that's tapped into the run position wire, run that to the shifter button, and then back to the starter trigger wire. This way the key has to be in the run position, or the push button starter won't fire. And since the starter trigger isn't connected to the ignition switch, turning the key all the way forward won't do anything.
do you know where I can find a wire diagram for the 03 Trailblazer Ignition Switch, so I can figure out which wires are which? everything on google images is a blurry unreadable mess.
 
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Daniel644

Daniel644

Well-Known Member
Check the link in @Mooseman's signature :thumbsup:
digging through the wiring diagrams all I can find is a Starting Circuit Diagram that only shows 2 wires of the wires on the Ignition Switch, the Red (constant fused power from the battery) and the Yellow that looks to go out to the relay but also goes through the PCM (if i'm reading it right, Page 70 of the 2002 wiring PDF for reference), there is also the Power Distribution diagram (page 49) which shows an Orange wire that only gets power with the key in the run position.

From what I can tell (including watching some videos of ignition switch testing on youtube) it looks like the yellow wire only gets power when the key is in the start position and so from what you are saying (if I'm understanding you right) to achieve what I want I would de-pin the yellow wire and extend it to one side of the switch then I would add a T into the orange wire and run that to the other wire on the switch, so I put the key in run, that powers the orange wire then the push of the button "jumpers" the power from orange to the yellow until I release the button which triggers everything that would normally be triggered by turning the key all the way to the start position. Do you think that switch can handle the current (there is a 10 amp fuse if i'm reading that right back at the underhood fuse box)? I suppose there is not a lot of current on that side since the Starter Relay is where the real current goes directly to the Starter Solenoid.
 

budwich

Well-Known Member
If the vehicle of "interest" is like most of the trailblazers, then the starter relay operation is totally controlled by the pcm (trailblazers have computer controlled starting) thru the "voltage sense" of the incoming yellow wire. Your methodology should work fine. You can probably check the current rating for the switch of interest by looking at the schematic for the TC system.

BUT be forewarned that your "jig" is good for you but maybe not good any one else who might borrow (officially) your vehicle as the button will always "powered" so to speak such that a person "playing" with the stick may "accidently" push the button while the engine is already in a "run state".... probably not good ... you know how people get the "wonder what happens". Of course, this "consideration" is not big but it is still worthwhile to mention it just in case... :smile:

Actually, I see that the powering of the relay itself has a "block" (park neutral switch) in line so you should be safe. My oops.
 
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Mooseman

Moderator
BUT be forewarned that your "jig" is good for you but maybe not good any one else who might borrow (officially) your vehicle as the button will always "powered" so to speak such that a person "playing" with the stick may "accidently" push the button while the engine is already in a "run state".... probably not good ... you know how people get the "wonder what happens". Of course, this "consideration" is not big but it is still worthwhile to mention it just in case... :smile:
That is a non-issue as the PCM will not allow the starter to engage while running. Try it :smile:
 
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Daniel644

Daniel644

Well-Known Member
[
If the vehicle of "interest" is like most of the trailblazers, then the starter relay operation is totally controlled by the pcm (trailblazers have computer controlled starting) thru the "voltage sense" of the incoming yellow wire. Your methodology should work fine. You can probably check the current rating for the switch of interest by looking at the schematic for the TC system.

BUT be forewarned that your "jig" is good for you but maybe not good any one else who might borrow (officially) your vehicle as the button will always "powered" so to speak such that a person "playing" with the stick may "accidently" push the button while the engine is already in a "run state".... probably not good ... you know how people get the "wonder what happens". Of course, this "consideration" is not big but it is still worthwhile to mention it just in case... :smile:

Actually, I see that the powering of the relay itself has a "block" (park neutral switch) in line so you should be safe. My oops.
this was actually the one concern I had about doing this, not so much about someone else playing with the button as I NEVER let anyone drive my cars (I fear the one time I do that person will wreck it and i'll be screwed by my insurance company for not having that person on my policy) but the possibility my finger might slip and hit the button, but it looks like that can only happen in Park or Neutral so it's less of a concern, still more of a concern then having to turn the key to the start position while in park or neutral, but less overall.

I found a post on TBSSOwners that showed a schematic for the TC logic system and the whole system is on a 10 amp fuse, so hopefully the switch is good enough, if not i'm hoping to set things up so it's just a matter of pulling the lower cover off the steering wheel and re-pinning the yellow wire to restore normal operation.


That is a non-issue as the PCM will not allow the starter to engage while running. Try it :smile:
so what you are saying is I "should" be all good with what i've described?
 

Mooseman

Moderator
The only thing I see is that while cranking with this external switch, accessories will continue to run. That's what the ignition switch does while in the crank position. relatively minor unless in cold climates where you need as much cranking power as possible.
 
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Daniel644

Daniel644

Well-Known Member
The only thing I see is that while cranking with this external switch, accessories will continue to run. That's what the ignition switch does while in the crank position. relatively minor unless in cold climates where you need as much cranking power as possible.
we rarely see temperatures below 10 degrees Fahrenheit and only occasionally even drop into the teens overnight on the worst winter weeks, so nothing like you guys can see up north and the truck is likely to become the weekend car within the next month or so, i'm looking at a C5 1SC with 70k miles if I can get the last 2k together before someone else beats me to it (seriously considering selling all my crypto holdings if I can't find a buyer for the Firebird).
 

Sparky

Moderator
That is a non-issue as the PCM will not allow the starter to engage while running. Try it :smile:
This. I absentmindedly attempted to start my already running truck and it did nothing aside from briefly confuse me why my starter didn't crank, and a facepalm quickly followed.
 
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Daniel644

Daniel644

Well-Known Member
OK, tried some preliminary proof of concept testing and i'm stuck, from the Ignition Switch wiring (harness on the very bottom of the column in the pics) the Yellow wire is hot only on crank, White is hot anywhere other then OFF, Red is hot all the time, Orange is hot in run, Pink is hot in Run or Start, there is a Red/White up behind the red that is also hot all the time, so in theory jumping the yellow to any of those other wires should produce a crank with the key in RUN, but absolutely nothing happens.

The only thing I can think is this cluster of wires going to the ignition cylinder in the other photo is reporting back the key position to the PCM, thoughts?
 

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budwich

Well-Known Member
:-( so I take it that you never see a ground action on the start relay when you push the button?
More than likely the pink is the key. Further, the key in run might not help you as the pcm might have some "carnal knowledge" that the system should not be in this mode... ie. start and run at the same time. :smile:

you might want to take a look at any info on adding a remote starter module to see what they do to get a truck starter. Yes, you have the key part covered but there might be other considerations that they cover.
 

budwich

Well-Known Member
a quick look appears to indicate your problem is with the orange... always oranges, dam citrus... :smile:
anyways, you can't have a hot on the orange as this is a run indication to the TBC which then prevents a start. :-( of course, this is in a 2008 but I bet its across years.

further, there might be more to it than that as the BCM has a bunch of "power status lines" that probably need to be followed for a start condition.... probably for things like hot wiring, starting while running, etc. This looks more complicated but again maybe the remote start gang has some insight... me I still go out in the winter to start my truck or leave it til it warms up outside... :smile:
 
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Daniel644

Daniel644

Well-Known Member
I found this video of a push button start on youtube but the guy didn't document what he did

I also found this TBSSOwners posting (post #6) https://tbssowners.com/forums/general-tbss-questions/77940-push-button-start.html where a guy has it, then the next post after that is the guy from the video above.

then there is this thread https://tbssowners.com/forums/exterior-interior-mods/13684-engine-push-start.html where in post #4 he says it's just 2 wires, a 12 volt power and Ignition wire but doesn't really go into much detail. Is there something radically different about the SS ignition system?


@budwich if it's just a matter of killing the orange I think a simple relay circuit like the top one in this image https://images.app.goo.gl/pmcx9gQ3v1FM7QUE6 would work, you substitute the orange wire coming out of the ignition switch in place of the battery in the diagram and the yellow light is the always hot in run the car would expect to see, but when you push the button the relay jumpers to the green light (yellow starter wire) which cuts the continuous flow of power along the orange circuit in run so that would function as though you turned the key to crank. I still think something may be up with those wires going all the way up to the cylinder but I can't figure out what they are.
 
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budwich

Well-Known Member
don't know.... but you need to meter your "modified" start circuit to see what is and what isn't happening in your case... basically are you getting voltage at the start relay, are you getting ground, are you getting voltage to pcm start signal? Go from there.

As for the "modified start circuitry" posted, any system / relay that basically results in a "mimic" of the key function will work.... cutting power to the orange while "push button starting" should work. Again, current loading on the components involved (ie. relay contacts) are important.

NOTE: as you go down this "hole", there is usually always a "rat" waiting... :smile: In this case, this platform is noted for its ignition switch issues (causing a broad range of problems). You are now "touching" some potential areas that could result in "unexpected stranding" which isn't a big problem IF you know how to get around things there after. Obviously, when things are working, its cool, but when / if they go south, especially at the wrong time, then you get to have "fun".

Having said that, you ask "if it is just a matter of cutting the orange"... I don't know because there is the "steady state circuit diagram" and then there is the "system response black box stuff"... which isn't really laid out well anywhere. That means disconnecting the orange to see what the response is to your "mod experiment".
 
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Daniel644

Daniel644

Well-Known Member
NOTE: as you go down this "hole", there is usually always a "rat" waiting... :smile: In this case, this platform is noted for its ignition switch issues (causing a broad range of problems). You are now "touching" some potential areas that could result in "unexpected stranding" which isn't a big problem IF you know how to get around things there after. Obviously, when things are working, its cool, but when / if they go south, especially at the wrong time, then you get to have "fun".
the funny thing about that is the guy in the video did the push button because of problems he was having with the ignition switch, if you go to his youtube channel and look at the video posted before the push button start one, it's him showing nothing happening when he turns the ignition to crank.


I don't have an account at TBSSOwners and don't think signing up for one to bump a 10 year old thread is good forum etiquette, especially since who knows if these guys are even still active over there. It's just bugging me that with several people having done it that none of them documented what they did.
 

budwich

Well-Known Member
i am sure there are a "few" videos on how to hot wire a car... doesn't mean it works for everyone...:smile:

Personally, I don't see a problem in what you are trying to do... you just need to follow thru. When things don't work, do some measurements and checks and go from there. As you indicate, it isn't "rocket science" and others have done it... :smile:
 
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Daniel644

Daniel644

Well-Known Member
i am sure there are a "few" videos on how to hot wire a car... doesn't mean it works for everyone...:smile:

Personally, I don't see a problem in what you are trying to do... you just need to follow thru. When things don't work, do some measurements and checks and go from there. As you indicate, it isn't "rocket science" and others have done it... :smile:
I just wish I knew how they did it so I could do it too.
 

Hobbyist4Life

Well-Known Member
This is most definitely an interesting thread. I'll keep an eye on it.

I've been researching the pas couple of months about the remote start systems and the installation process and such as I will be attempting to install one after a couple of months when I finish my University studies and and get back home.

One important part that I see missing in your logic is, as you said, related to the wires going all the way up to the cylinder.

If I remember correctly, those wires are there to check if the key is in the crank position. I'm not entirely sure about this, but AFAIK you can bypass that by turning the key to the crank position and check what resistance it's providing. Then all you'd have to do is connect an equivalent resistor to the harness and voila! (not entirely sure about this theory, but I believe that should be it)

The bypass module that is needed for remote start systems is used to mimic having the key inside and allows the car to run.

For testing this, I would highly suggest removing the ignition switch, and then using a key turn the teeth twice to mimic going to the run position. Keep it in that position and put your key in the cylinder and turn the key all the way to the cranking position. At this stage (or earlier), disconnect the wires going to the cylinder and check what resistance is it's resistance that'd be the resistor you need to buy. But before pulling the trigger, just as a proof of concept, reconnect the cylinder wires and try to start it using the push button theory that you tried earlier.

The only difference between this state and the state that you tried before is that now they key is "seen" as being in the crank position. If it starts then all you have to do is put the aforementioned resistor in the connector of the cylinder and call it a day.

I, for one, was fiddling around with the ignition switch one day, and turned the teethe of the ignition switch all the way to crank, but the car wouldn't start unless the key is in the cylinder AND turned to the crank position. I'm not sure however, if I tried while the key is in any position other than crank. That was a like 9 months ago.

Keep us updated!

Regards,
H4L
 
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I have a remote start on my 2007 Trailblazer. The bypass module does all the work for the starter, door locks etc. I used the Direct Tech DBALL2 and it interfaces with the OBD2 Port. See these instructions on the12volt.com
 

Hobbyist4Life

Well-Known Member
He doesn't want to install a remote start system, he simply wants to push a button to start the car, instead of fully turning the key to crank. So going through the hassle of adding a bypass module would over-complicate what should be a simple wire splice.
 
I completely understand he is not trying to install a remote start. The instructions and information I linked to were referenced above. Also the aftermarket industry has already accomplished the task he is trying to do. It doesn't matter if you are using a wireless remote control or a button on your gear selector. The theft systems still need to be bypassed properly and the ignition system and starter powered in the correct sequence or you risk damaging your vehicle or not accomplishing your goal.
 

budwich

Well-Known Member
I just wish I knew how they did it so I could do it too.
I wish you did to... but wishing ain't going to do it. :smile: you are basically there all you need to do is checks of the system when it doesn't work as expected to find out what is missing / happening.

The way it currently stands... you haven't really posted a complete description of what you tried and what the result was / is. Wish you would follow thru... :smile:
 
You don't have to use the bypass. Besides ease of install the main reason is to simulate the key for the theft system (and other convenience features that don't apply here). You will have your key in the ignition. What you won't be doing is turning the key and that is what you need to "bypass". The ignition system is looking for a certain sequence of events to trigger a start scenario. Key present, correct key verified, ignition 1 on, accessory off, ignition 2 off, voltage change on the starter wire etc. The engine fires the starter stops, ignition 2 turns back on, accessory turns back on. These are not specific nor are they in order. This is only an educated guess without probing my ignition with a logic probe again or looking at schematics.
 

Hobbyist4Life

Well-Known Member
Try to test it as I mention earlier first, and go from there... Put the key in the run position, then slide the ignition switch outside. Use another key or something solid to turn the teeth to the crank position. If the car starts, then you don't need to do the bypass part. You would just have to use the relay diagram you showed earlier (post 17) to disconnect accessory when trying to crank it.

I'd try that first and go from there. Just make sure you keep us updated with what happens.

I'll be able to test this on my car when I travel back home (after 11 days :woohoo:). Until then, it's all you.
 

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