ignition switch use to turn on now it wont

2004 Chevy Blazer has a "Passlock" security system. The keys are not chipped, so I don't believe the battery replacement would be the cause. Is the "Security" light lit on the instrument cluster?

I believe your issue is the ignition switch itself. Blazers are notorious for ignition switch failure. There may be a tumbler getting hung up inside the ignition cylinder. Your key may be worn. Do you have a better cut key? Spare key?

thank you i had to bypass that awhile back i bought a battery from AAA club wasnt the best fit for my beautufull beast the radio played and lights worked she sat all winter sent that battery back and purchased i a optima red top the ignition key wouldn't turn now could it be i didn't put battery terminals tight the whole way or other if that needs replaced it was tampered with wouldnt you think please respond and thank you

I have to stress that the Passlock system will not stop the ignition switch from turning. The Passlock security system is enabled (via wrong key, or simply no key) the vehicle will turn over, but not start. So if you cannot turn your ignition switch as I understand (front or back), the problem lies within your ignition switch or you're trying to use a severely worn key that is not engaging the tumblers.

thank you its weird how it would go bad just sitting. key aint worn

Last ditch effort... Try spraying lubricant into the ignition cylinder and ramming the key in and out. Try jogging the steering wheel back and forth. Jog the shifter, press the brake.. Anything to try and get the ignition to turn. Good luck!

i will try that... did... most that but the lube ing,,, thank you much will let you know im stopping for now looks like its going to rain storm

Hi I have a 05 trailblazer that wont start in Minnesota. . It has power but no sound at the ignition (ie) clicking or anything .. acts like she is dead.. but has a good battery and the blower motor sounds strong and has lights...

he is right no CHIP but the key has a small cut at the end slanted on each side to activate a contact.. you have to file the end of the key if the key turns but states security service..then match the key with a dealer and have it cut right..

abs and brake light are on cant turn the key off the key is stuck on and running

I HAVEa problem my will turn backwards but would not turn forward to start the car

My nephew has a 2001 chevy trail blazer. it would not start after he put the key in ignition but it turned back & forth with ease. Too loose. Does anyone think the tumbler shld b replaced?? Tx

I have changed everything in my 03 trailblazer on why it would start then wouldn't drove it for 7 weeks an did it again now just had a new key made by GM cause the keys did not match up plus old one looked very worn out make sure the key says GM on it

i have a 2006 trailblazer it will start and run but will die for no reson let it set for about 30 sec to 1 min and will start and go again but will do the same thing again repeat and start and go again but everything work just wont start till you let it set for 30 sec to a min what is wrong and what do i do to fix this. thank you billy

I have a 2004 trailblazer that will only start when jumped(weve gone through 2 new batteries) once it is jumped it will start on its own for about a day and then need to be jumped again. Once it dies, you can not remove the key until it is jumped again, also the security light is on. Can anyone help me with this.

I have 2003 Chevy trailblazer EXT The key will not turn to crank up the truck

Yesterday my 2003 trailblazer with key off and out had power windows, radio on, battery light on, rear window went down on its own...it died over night.. this morning I put a jump box on it, while it charged I ordered a ignition switch online... I started my truck that I out on charge and went and got the new ignition switch... Came home disconnected the battery.... Replaced the old switch with the new one... Problem solved... Hope this helps everyone out.. 15 minutes and back to working properly... Have a great day... I figured it out by youtubing and reading these forms all night. Great place to find the answer to a problem.. have a great day I'm a chevy guy