I have a 1999 blazer and changed battery and now the stereo requiers a unlock code. what is the code and how do I install code

 

Sounds like either a former owner or yourself had activated the Passlock security feature and it worked like it is supposed to. I believe you will have to get the code from a GM dealer.

 

sounds like thats the issue. I have no clue if/how much they will charge you but be prepared!

 

I hope I am not to late to help you with this and save you some money.

I just bought a Blazer this week with loc displayed on the radio.
I was quoted 70 dollars by my local Chevy Dealer to fix this and it couldnt be simpler to fix. They are ripping people off.

Grab a pencil and paper and head out to your Blazer.

Hold down the 1 and 3 presets on the radio until the loc changes to a 3 digit code and write that down.

Now press the am/fm button and you will get a second 3 digit code. Write this down next to the first three digits so you end up with a six digit code.
(Note: After you get the first three digits I think you have about 10 seconds or so to hit the am/fm button and get your second set of digits. Just start over if you wait to long.)

Grab a phone and dial 1 - 800 - 537 - 5140
(You wont be talking to anybody your just going to put in numbers.)

When it asks you to press 1 for this and 2 for that and all that just input:
620529
and that will tell it that your calling about chevy and you have authorization.

Next it will ask you for the six digit code from the radio which you wrote down earlier.

Once you give it that, it will then give you a 4 digit code to put into your radio. Write it down.

Head back out to your Blazer and use the hr and min buttons to make it display the 4 digit code you got from the phone.

For instance: if it was 0108, your going to press the first button until 01 displays on the left and the other button until 08 displays on the right. (NOTE: My 2001 blazer only displays 3 digits so the left side will just display 1 and not the 0 and would look like this on the radio 108.)

Anyways, once you have that in, wait a bit and the radio will say "sec".
Next thing you know its unlocked.

Also note, you can no go through this process on the radio to remove the code altogether and or make your own code for the future.
I chose to just keep my code and have it written down for the future if or when I lose power.

Hope this helped.

 

^^^^^^^^That looks and sounds correct to me.^^^^^^^^^ Th e only thing is, is if you try to unlock it 3 times and it does not unlock you will need to leave the ignition on for about an hour to reset the system. BUT NOT RUNNING!!! And then retry the codes.

 

Great information, didn't know you could reset it by yourself.

 

Great info Grawbad... just replaced the battery in my blazer. going out to log all you listed info after i get out of class. Thanks a lot for the info!

 

I'm on my third battery and never had this happen??? Good info to know regardless!

 

ok so i tried this this evening... didn't have any success. is the ignition thing accurate? really wish i could work around leaving my key in the ignition for a hour if possible....

 

hey guy's figure i would share a little info. just got my radio unlocked but had a few different numbers than the ones that were posted above. i had to hold down 2 and 3 preset buttons. then got first code and hit am/fm for second. when i called the phone number i had to enter dealership number 206053. i also entered the one above and found out theres another one 139010. the one above and the 139010 was declined for me. 206053 is the one that worked. hope this helps out! if not do a simple google search. thats where i got this other info.