I got a 1999 chevrolet tahoe. when i put the key in the ignition the head lights,and the dash light comes on but it won't even turn. i change the starter and got a new battery and it still won'

bad ground somewhere once you get a bad ground somewhere it will trigger other devices

the way i reset the antitheft is to put the key in the ignition and turn it on till all the dash lights come on but dont start it let it sit 15 minutes turn the key off and turn it on again till all the lights come on again repeat this procedure three times after the third time turn the key off for about 5 seconds and then your car should start hope this helps.

Sounds like the ignition switch is worn out(or the linkage from the lock cylinder to the switch has come loose or something like that)

The security light is a visual indication that something in the car's antitheft system is failing. In most GM cars and trucks there is a hidden system that most people are unaware even exists. From the moment you put your key in the ignition, there begins a constant line of communication between your key's security chip or transponder, to the ignition's lock cylinder, and then to the car's TDM. (Theft Deterrent Module) The TDM is what tells your computer that the correct key is being used and that it is "OK" to allow the vehicle to start and run. These 3 parts must be in CONSTANT communication. If the key is in the ignition, then these parts are sending important signals to each other. The security light illuminates when that signal gets broken, even just for a second. When the signal breaks, (normally due to a failing/broken part) the car goes into antitheft mode. The car misinterperates this and thinks its being stolen or hotwired because it is NOT getting that signal from YOUR specific key. There is where the security light turns on and shuts down your vehicle. So basically, if that light is on, your system has some sort of failing part. This can start as an intermittent "no start", to your vehicle not running for days at a time, to the vehicle NEVER starting again. The problem is electrical and computer based, so don't count on an easy reset button, or the problem fixing itself. The hard part is isolating which part is the problem. You can spend a thousand dollars through a mechanic very easily. I have had great luck with bypassing the entire system. This way the problem will never return. It actually CAN'T ever return because it is eliminated. This can also be done yourself at a much cheaper cost. Read through this link very carefully. You'll find alot of information and pictures, along with ways to help you fix this.



http://vatspasslockpasskeysecurityhelp.yolasite.com/

ignition switch contact or starter motor given up the ghost ,try a jump start and see if that works ,do the lights go dim when you try to start it??if so then its a flat battery or a old battery thats just died on you.These vehicles do have a big ignition lock in the dash and these just dont go wrong like a VW but its possible?

The pass lock is beginning to fail.You can try reporogramming it following this procedure. If it still continues to happen the pass lock/ignition tumbler may need replaced.
PASSKEY LOCKOUT RESET ALL GM CARS 1999 AND UP
1) Put the key in the ignition and turn to the "ON" position. Leave it that way for 10 minutes. After 10 minutes turn the key and take it out. Repeat this process (2) more times (3 times, 30 minutes total) This should reset the PASSKEY system to recognize your key.

The brake switch is bad.

Turn the ignition to the on position so dash lights come on, but do not start. Now pump the accelerator pedal three times quickly. The light will go off for another 3,000 miles

it sounds like the problem but the question is why wont the pcm start the car. with the key turned to on the service engine light sould be on. if not the pcm has no power.

aftermarket radio ? dimmer cicuit in radio harness for dash lights fuse illumination good?