neutral switch
Then turn it off after it is put into park
Frozen/seized clutch pack, time for a rebuild.
did you check your battery and alternator?
Older Chevy's have a steering lock when the key isn't in the ignition.
Ran out of gas? Or ran out of oil?
A wire that is getting hot could be shorted to ground.
Starter, battery, battery connections, neutral switch,
Mine turns on while parked and wont turn off till I start it. Its a problem with the BCM. Body control module.
TRY TURNING THE KEY OVER.
If the turn signal bulbs light but will not flash, the flasher relay is defective, replace it.
Have you tried placing the car in park and or nuetral? possible neutral safety switch failure.
Check the brake light switch.