Can't get shifter into park

Shifter not coming out park could be a problem with the shifter interlock system . Won't let driver shift into gear unless foot is pressing the brake pedal down .
locked light on ? Do you mean SECURITY light is lit on the instrument cluster . Anti-theft system disables fuel injectors if there is a problem .

shifter cable is streched, you can adjust it.

Your shifter is a column shifter, not a floor shifter, right? Is the headlight switch mounted on the steering column? If so, then this "combination switch" may be the problem. If not, start looking for loose wires, especially ground wires, around the steering column area and the headlight switch area.
It would also be a good idea to get access to a wire diagram from a factory repair manual and find out if GM had any Technical Service Bulletins addressing this problem. If I get a chance, I will ask around and see if any of my co-workers ever heard of this problem.

You've pretty much answered your own question, although I doubt it's demons...LOL. Ign switch, nuetral safety or park switch, shorted starter, could be chaffed wiring. If your in the ON position and the starter engages, I'd be looking at the ign wire from the switch to the starter solenoid and or relay. Your car is 20 years old so anything is possible at this point. Your best bet is to go to ALLDATA>COM and buy the wiring schematics for your car grab a DVM and start checking your circuits.

This generation of Buick seems to have a faulty speedo cluster illumination circuit.
I have an '01 and an '02 and they both have the same problem with the dash illumination.
I use the 'FEEL' sollution ;
When you start the car you can assume it is in PARK.
the next spot down with the shifter is REVERSE.

Next is going to be NEUTRAL.

And then DRIVE.

So, from PARK , 3 possitions down on the shifter is going to give you DRIVE.

The alternative is to replace the instriment cluster on you car.

{: ) I supposed you have checked the fuses at the IP fuseblock and tried adjusting the dimmer knobs back and forth. You can also try to check the cluster connector behind ( although not likely to be the cause). If the illuminations or backlighting works fine on other areas except the cluster, and gauges functions are fine, you will need to replace IPC (cluster) and program. Actually there is a GM bulletin for this kind of concern for the 2007 IPC poor backlighting. The IPC should be replaced with a 2008 hardware/software.

when this happens, have some one look at your brake lights to see if they are lit while you depress the brake pedal. if the light are not lit then the brake light switch is bad.
if the light are lit then the shift interlock solenoid under the shifter is bad

Yes. Check your body grounds also and make sure they are clean and tight.

I had the same problem. My backup lights wouldn't come on in when I put the auto. trans. shifter into the Reverse position. They WOULD come on briefly as I moved the shifter from Park position into Reverse, but would go off again when the shifter reached the Reverse detent. I got the solution from the Haynes service manual, in which the relevant switch is referred to as something like the neutral safety switch. Check on top of the steering column close to the firewall. Set the parking brake, then move the auto. trans. shifter into Neutral position. Get under the dash and rotate the neutral safety switch clockwise as far as it will go. Then move the shifter into the Park position, and your switch should be set. If the backup lights don't come on now when the shifter is put into Reverse position with the ignition switch 'on', there may be another problem.

change the gear box and expensive for u haha cause its auto mines manul