Check\replace the neutral safety switch.
Under the hood beside the battery.
The battery is located in the back seat - you take out the back seat by pulling up from the floor - then lift out - the battery in on the passenger side.
The switch is just across from the battery located in the rad reservor, to remove it and clean the sensor probe, you have to remove the battery.
I have a 92 Le Sabre and I've never seen a reset switch !
Dead cell in the battery or some light is on pulling power from the battery. A stuck relay can also run the battery down.
Any of the following.... Bad battery, bad starter, bad ignition switch, bad neutral safety switch
you either have a diying battery or a ground short
where is temperature switch on 1996 buick regal
Buick does not use a reset switch.
Replace ignition switch for 1993 buick century?
Where is the backup light switch on a 2002 buick century?
what size of car battery do i need for a 2003 buick lesabre