How to turn off traction control on 2005 Chevrolet Trailblazer

First you need to have EBCM - electronic brake control module check for DTC'S - diagnostic trouble code's . If the light is on there is a code stored . I think most part stores can do this and for free . After you find out what code is stored , looking up that code in service repair information for diagnostic trouble shooting chart would be next step . There are a few codes too.
DTC C0035 or C0040
DTC C0045 or C0050
DTC C0110
DTC C0131
DTC C0161
DTC C0186
DTC C0196
DTC C0201
DTC C0240
DTC C0241 or P0856
DTC C0244 or P1689
DTC C0245
DTC C0283
DTC C0287
DTC C0290 or C0292
DTC C0455
DTC C0550
DTC C0558

Find the code do the diagnostic's , fix the problem , wiring issue's , a sensor , bad module ,what ever it is . The light will go out then . Here is a sample of code discription .
• DTC C0035 Left Front Wheel Speed Sensor Circuit
• DTC C0040 Right Front Wheel Speed Sensor Circuit

StabiliTrak service light - Chevy TrailBlazer, TrailBlazer SS and ...

forums.trailvoy.com > ... > 02-09 General Tech Q&A > General

Dec 24, 2009 - 11 posts - ‎7 authors
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Traction control is for safety. It reduces wheel spin. When it is turned on it is harder to lose control in slippery road conditions. Like doing donuts in the snow.

The traction control uses the ABS wheel speed sensors (1 on each wheel - usually in the wheel bearing assembly). The speed sensor is for your speedometer. Do you have an ABS light on too?

traction control faulty. You slip and slide, your traction control activates, then here lies your problem.. after your traction control activates, it is creating an electrical short, vacuum leak, etc. look at what your traction control is operating, probably brakes. SO look at the brake booster vacuum lines or connecitons. Hope this at least gives you an idea of where to look. COuld be your traction control module is faulty.

It means to service the 4wd system, you will have to have the truck scanned to better diagnose.

THe Traction Control System uses the ABS sensors for info. Any problem with them affects the Trac. system.

ref. link:
http://www.tbssowners.com/forums/general-tbss-questions/71077-no-traction-control-button-switch.html

To disable the Traction Control and Stabilitrak depress and hold the button under the large engage button on the shifter. There may be an issue with the idle speed adjustment for operating with the TC/S enabled.

Do you have 4WD selected? When in 4WD and turning there is some resistance in the drivetrain.

yes they will be slightly more narrow but you will not have any traction or speedometer problems.