So I have to replace the key cilinder in my 99.

1. Disconnect� negative� battery� cable.� Disable� air� bag� system.� See� appropriate� AIR� BAG� RESTRAINT� SYSTEMS� article.� Remove� lower� left� insulator� panel.� Disconnect� 2� Yellow� 2 way� SIR� connectors.� Remove
tilt� lever.� Turn lock� cylinder� to� RUN� position.� Press� locking� button� on� back� of� steering� column� housing� assembly.� Remove lock� cylinder.� Disconnect� ground� strap� from lock� preload� spring� (if� equipped).� Remove
lock� preload� spring.
2. To� install, � reverse� removal� procedure.� When� installing lock� cylinder, � ensure� sector� is� in� RUN� position.� With� key� in lock� cylinder, � align� locking� tab� with� slot� in� housing� and� press� into� position.� To� complete
pay particular attention to air bag deactivation. If there is a proble whn install take to a professional to fix it right. You can destroy the airbags which is about $1000 to fix plus the windshield

Disabling� &� Activating� System� (All� Other� Models)

1. Turn� steering� wheel� to� place� wheels� in� straight ahead� position.� Turn� ignition� switch� to� LOCK� position, � and� remove� ignition� key.� Remove� AIR� BAG� fuse, � AIR� BAG� 1C� fuse, � or� Supplemental� Inflatable� Restraint
(SIR)� fuse� from� instrument� panel� fuse� block� (underhood� junction� block� on� Park� Avenue).� Wait� at� least� 10� MINUTES.
2. Remove� knee� bolster, � sound� insulator, � or� trim� panel� (as� necessary)� from� under� steering� column.� Remove� Connector� Position� Assurance� (CPA)� clip, � and� disconnect� Yellow� 2 pin� connector� located� at� base� of
steering� column.� See Fig.� 2� or Fig.� 3�.

NOTE: On� "C"� &� "K"� Pickups, � Cavalier, � Century, � Grand� Prix, � Intrigue, � Regal, � Sierra, � Suburban� and� Sunfire, � passenger side� air� bag� Yellow� 2 pin� connector� is
located� near� base� of� steering� column.

3. On� models� with� passenger side� air� bag, � remove� knee� bolster, � trim� panel, � sound� insulator, � glove� box� or� glove� box� door� (as� necessary)� from� right� side� of� instrument� panel.� Remove� CPA� clip, � and� disconnect
passenger side� Yellow� 2 pin� connector� from� passenger� inflator� module� pigtail.
4. To� activate� air� bag� system, � ensure� ignition� switch� is� in� LOCK� position� and� ignition� key� is� removed.� Connect� air� bag� module� Yellow� 2 pin� connectors.� Install� CPA� clips.� Install� AIR� BAG� fuse, � AIR� BAG� 1C� fuse,
or� SIR� fuse.� Install� knee� bolsters, � sound� insulators, � trim� panels, � glove� box� or� glove� box� door� (if� removed).
5. Staying� well� away� from� air� bag� modules, � turn� ignition� switch� to� RUN� position.� Ensure� AIR� BAG� warning� light� flashes� 7� times� and� stays� off.� If� AIR� BAG� warning� light� does� not� operate� as� described, � see SYSTEM
OPERATION� CHECK.

NOTE: When� fuse� is� removed� and� ignition� switch� is� in� ON� position, � AIR� BAG� warning� light� will� be� on.� This� is� a� normal� operation� and� does� not� indicate� an� SIR� system