My car has a flashing light on the dashboard of a lock button symbol

The yellow car and lock symbol that appears on the dashboard of your Pontiac G6 indicates that the vehicle's security system has detected a problem. This symbol may appear if there is a malfunction with the system or if the system has been triggered by an event such as a collision or attempted break-in.
If the security system is functioning properly and the yellow car and lock symbol is still displayed, it is possible that there is a problem with the security system sensor or wiring. It is recommended to take the vehicle to a mechanic or a Pontiac dealership for further diagnosis and repair.
In the meantime, you can try pressing the unlock button on the remote or using the key to unlock the doors and see if the symbol disappears. If the symbol remains displayed, it is possible that the security system will need to be reset by a professional.

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A possible dashboard symbol:

https://www.directline.com/car-cover/understanding-car-dashboard-warning-lights

"Brake system light. The first thing to do if you see this symbol glowing on the dashboard is check the handbrake hasn't been left on. ... That could relate to the worn condition of the brake pads or discs, a lack of fluid in the system or a problem with the anti-lock brakes (ABS) or stability control (ESP)."

Make, model and year of automobile.

Color of dashboard symbol or icon, and is it flashing?

run the fault code
it could be a problem immobilizer system , fob key battery

Check in your owners manual,it will show you all the symbols on your dash.

If i had a idea what the symbol on the flashing light looked like i might have a better idea as to what it could be .

That's the symbol for your anti theft system.

Battery Constant 12v+ Positive Wire (+): Black/Yellow
Battery Constant 12v+ Positive Wire Location: Ignition Switch Harness

Starter Positive Wire (+): Blue/Red
Starter Positive Wire Location: Ignition Switch Harness

Ignition Positive Wire (+): Red
Ignition Positive Wire Location: Ignition Switch Harness

Accessory Positive Wire (+): Red/Yellow
Accessory Positive Wire Location: Ignition Switch Harness

Parking Light Positive Wire (+): Red
Parking Light Positive Wire Location: Low In Drivers Kick Panel

Power Door Lock Negative Wire (-): Add Actuator. This vehicle uses a central door locking system. When connecting a keyless entry, you will need to add a door lock actuator and some units will also require (2) extra relays.
Power Door Lock Negative Wire Location: To Drivers Door Only

Power Door Unlock Negative Wire (-): Add Actuator. This vehicle uses a central door locking system. When connecting a keyless entry, you will need to add a door lock actuator and some units will also require (2) extra relays.
Power Door Unlock Negative Wire Location: To Drivers Door Only

Door Trigger Negative Wire (-): Red/White
Door Trigger Negative Wire Location: In Black Plug, Above Hood Release

Domelight Supervision Wire: Use Door Trigger, Requires Relay
Domelight Supervision Wire Location: N/A

Horn Negative Wire (-): Red/Green
Horn Negative Wire Location: At Steering Column Harness

Tachometer Wire Negative Wire (-): Black/Blue
Tachometer Wire Negative Wire Location: At ECM, Under Drivers Side Dash

Brake Light Positive Wire (+): White/Black
Brake Light Positive Wire Location: At Switch Above Brake Pedal

CODE ALARM SYSTEM

Used on:
Impreza 1996-2001
Legacy 1995-1999
Forester 1998-2000

Battery GP-23A

Lock: Left button will lock all doors. Double chirp indicates locked.
Unlock: Right button will unlock driver's door only. Hold unlock button app 6 seconds, it will unlock all doors including rear gate. Single chirp indicated unlock.
If the car chirps or lights flash 4x the alarm was triggered.
Panic. Press both buttons to activate emergency honk and flashing lights.
Valet mode: With optional alarm onlyPress the red alarm button on the left of the steering wheel. The light will quickly double flash. To re-set back to normal mode, press the red alarm light button again

Battery failed and lights flashing?
Parking lights will flash when the vehicle's battery is disconnected and reconnected.
To stop lights from flashing, either:
Press remote transmitter "UNLOCK" button once OR turn the ignition switch to the "ON" position and press programming button for one second (see below).
The vehicle interior (courtesy) light and door open warning light (DOOR AJAR indicator) will then illuminate for 60 seconds when the ignition is turned off, or until the doors are locked with the remote transmitter. Yes, the dashboard instrument panel lights will flash when the parking lights flash.

Programming or Overriding the Alarm when you have lost the remote
Open driver's door.
Turn ignition key to 'On'
Press and *hold programming button* in (see diagram, button under dashboard)
After 15 seconds the the door locks will cycle 3 times. Do not release Programming button.
Press lock (left) button the remotes to be programmed. The door locks will cycle one time. Exit programming mode by releasing Programming button under dashboard and turning key to off.

Code Alarm Programming Button is under dashboard on the kick panel by the driver's left knee, left of the steering column. If you can't find it, it might still be tucked up in the wiring harness higher up in that same general area. The botton is recessed in a plastic ring (see diagram).
This button must be pressed while programming remotes or if the battery was disconnected and the lights are flashing.

Security lights. Is it a GM vehicle? It is normal when the key is out for the security light to flash

THE S LIGHT BLINKING ON THE DASH STANDS FOR SPORT NOT SERVICE IF YOU LOOK ON YOUR SHIFTER YOU HAVE A LITTLE BUTTON IF YOU PRESS THE BUTTON YOUR CAR WILL DRIVE ON SPORT IF YOU REASEASE THE THE BUTTON YOUR CAR SHOULD DRIVE REGULAR.
I hope this helps
Sam

Try pressing the D3 button on your gear shift - little button below the main one. D3 allows for quick acceleration, but the light also shows when the car is locked is gear ('limp home mode') due to another problem.