I am in need of some major help! I have read the postings and replies on this site and tried all of them and still have had no luck. The security light is locked on and wont allow my 99 chevy blazer to start. We had to replace the key and cylinder because it was not working any longer and have tried to reset the computer by unhooking the battery so we could do the relearn phase, but it wont erase anything. The radio stations and clock are still the same. We even bought a code reader to maybe get the codes to reset the system, but no codes appeared so that method did not work. Next, we bought a volt meter to get OHM reading to place a resistor inline to trick the computer, but after cutting the wire it gave us no numerical readings to use...just showed 0. If anyone else has any more ideas, it would greatly be appreciated!!! We are at a loss right now and can't afford to tow it to dealer for them to fix it.
Thanks

 

If the DIY method for the passlock relearn does not work, you will have to get the force relearn done by someone with a Tech2 or equivalent high feature scan tool. There is no way around it.

As a temporary work around, turn the key on and wait 10 minutes for the security light to go out, then you should be able to start the truck and have it stay running. Not ideal, but if you absolutely have to drive your truck, it should get you from A to B.

 

Thanks for the reply so quick but we have tried that method too of turning key on and waiting the 10 min, but the security light never goes off. It stays on constant. I think its because the memory is still stored in the computer, but we can't get the computer to reset at all. Will the force relearn method work if the memory wont erase? Im up to try anything at this point

 

You may have to consider that there may be other problems contributing to your current condition... Disconnecting the battery for 30 minutes or so should reset the PCM. Waiting for 10 minutes should allow the vehicle to start and run, but the security light does need to turn off for that to happen. Sounds like you have deeper problems. Getting it to someone that knows what their doing would be the next step I would propose.

 

My husband's Burban did the same thing... no matter how long I waited before starting it. We ended up having to take it to the Dealer so they could put a new system in it...