What is the red blinking light on the dash 2004 sierra?

The red blinking light on the dashboard of a 2004 GMC Sierra typically indicates a security or theft deterrent feature is activated. This light may blink when the vehicle is turned off, signaling that the anti-theft system is armed. If the light stays on while driving, it could suggest a problem with the system or that the vehicle is not recognizing the key. If you're experiencing issues, it's advisable to consult the owner's manual or a mechanic for further assistance.