How to replace a key lock cylinder on a 99 chevy lumina v6 3.1

I just did that last week. Remove horn, remove steering wheel, remove blinker switches, remove tilt spring, remove tilt mechanism, remove key buzzer switch (mine was white with 2 small wires leading to it). Screw holding ignition cylinder in should now be visible. P S Let me know if you have any trouble removing all the items listed above and I will try to help.

Coil, plug or spark plug wire

The trunk release button should be located in the glove box. mine is a yellow button and yours should be too.

you have to remove steering wheel then turnsignal switch to access retainer screw for lock cylinder. remove screw and cylinder will pull out.

the two small wires that attaching to the lock is very easy to break. if you did not carefully install it then it will break .as you turn the key the wires will move back and forth. you need to check that again

After the steering wheel is removed, and the lock bolt is removed, you can pull out the lock cylinder. You may need to carry the column to a locksmith and they can handle taking out the cyl for you. You may be better to swap cylinders with your old one, or a new cylinder will come with a new key. Special tools are neede to remove the steering wheel and compress the spring for the lock plate.

SOUNDS LIKE YOUR LOCK CYLINDER OR ACTIVEATOR CLIP IS FALLEN OFF
YOU WILL NEED TO REMOVE DOOR PANEL
THEN IT SHOULD BE VISIBLE OF WHERE IT CAME LOOSE

If your lumina has a Pass II key, it may well be the ignition lock cylinder on the steering column. The car key has a resistor staked on the sides of it which is read by the theft deterent module. The theft deterent module issues a command to the ignition relay and the fuel injectors when it reads a correct resistance from the key. If the lock cylinder is damage( broken wire) ect. the theft deterent module will not be able to read the key. Unfortunately, if you have a Lumina with a solid shroud around the steering column, the dealer will charge you $700-$1200 to replace the cylinder.
Good luck

I think your question may have been cut off. Are you asking about the difference between a lock cylinder and starter switch?

I just changed both on a 1990 Lumina. As you turn the key a rod attached to the lock cylinder slides the starter switch between the different positions: Acc, Off, Run, Start. All the electronics are housed in the starter switch, while the lock cylinder manually places the starter switch in it's different positions. Does that make sense?

Typically new lock cylinders come with a new key.

I hope this helps! -Nick

Make sure you don't have the steering wheel locked. If the key still won't turn then you will have to replace the ignition lock cylinder. The gear shifter on any car should not move unless key is turned.