Electical problems 04 Chevrolet trailblazer the gauges don't turn off with the key and the battery light will come on.The security system wont arm sometimes and will leave the headlights on.The emergency brake light will come on while driving when ever it feels like it.If you pull the emergency brake lever it will sometimes disable my stereo.The gauge problem started today and everything else has been getting worse over the last 6 months.Oh ya one other thing the vehicle will die sometimes when you take off.Anybody got a answer.Thanks

I found this

Ok, do the following procedure if it does not work try it again with a new key if problem still exists the ignition switch/passlock sensor needs to be replaced then the following procedure will need to be performed again.

1. Turn key into on position with engine off.
2. Bump key into start position for a second without trying to start it and leave key in on position.
3. Leave key in on position for at least 10 minutes and security light will turn off.
4. Turn key off and wait 5 seconds.
5. Repeat steps 1-4 2 more times for a total of 3 times/30 minutes
6. Vehicle should now start.

Did you use the original key and lock cylinder? They are coded for the security system.

check fuses relays and battery --lights going on is not an indication of battery being good --test battery with a meter or try boosting but your problem more than likely is key or ignition switch check --your key if worn or have chip key and chip/battery fail truck will not start if you have the other key try that one or try the relearn for the passlock system the link has information on how to do it
http://forums.trailvoy.com/showthread.php?t=69908

Is the security light flashing? If it is, put the key in and turn all the way but don't start. Leave on for 10 min. Or until the security light stops flashing. Turn off and then try to start.

did you check to make sure the battery is fully charged?
On some GM products there are 2 large metal GROUND LOOPS bolted on or near the thermostat housing. Those are the main computer grounds. They are important. Make sure if you touched them they are both back on and tight.
Aside from the ground loop thing above, there shouildnt be anything youi would touch in a thermostat change that affects the starter, so for ease...treat it as a starting problem. It needs BATTERY CHARGED AND CABLES TIGHT. It needs GOOD FACTORY KEY (No security light or key symbol flashing on dash!), It needs SHIFTER IN PARK/NEUTRAL or CLUTCH FULLY DEPRESSED, and it may need alarm cycled OFF/UNLOCK even if the car isnt locked. Id start there. If all that tests out, then you may have a failed component in the starting system or an issue with security that needs to be checked. But start with those, most sudden start problems will fall in there.

If the problem is no crank, could be the security system, key switch, neutral safety switch, starter, cables, or battery.
I would check for power at the starer and work back.
Did you try it in neutral ?

Is the starter kicking out on it, you can check with a person on the inside turning it over. It kicks into the fly wheel.

Have the battery checked, if it has a flat cell you may experience bizarre problems
like my mothers lincoln did (radio problems, security system problems, etc.) I would
also check the ground connections to the block and the chassis (I often clean and file
the block before reattaching grounds). Also check under the rubber boots on the
positive for corrosion (which happened on my 04 S-10 and caused a similar condition).
Hope this is useful.

Try unhooking the battery, turn key on, leave door open, then connect battery, start engine immediately. The battery saver module thinks it's saving your power!!

That means there is a problem with the VATS System. This sometimes happens when the battery is disconnected for an extended period. You might need to do a relearn for the keys. You can get it done with the right scanner in 5 minutes, but there is a way to do it without one.

Turn the key to the start position, release it to the on position, then leave it on for 11 minutes, then turn it off. Repeat this sequence three times, and on the fourth try it should start if that was the problem.