The Airfoil Solution
At this point, I have had the red light problem for over a year. This weekend, in an effort to procure a means of listening to system sounds via an external source, I downloaded Rogue Amoeba's Airfoil program which allows transmittal of system volume through an airport express. Strangely, whenever the program boots up, it has the side effect of turning off the red light in the headphone jack and allowing access to the internal speaks. I am not sure if this will work in the same way for everyone, but it has been a welcome benefit to a program that has numerous uses. Hope this helps.
At this point, I have had the red light problem for over a year. This weekend, in an effort to procure a means of listening to system sounds via an external source, I downloaded Rogue Amoeba's Airfoil program which allows transmittal of system volume through an airport express. Strangely, whenever the program boots up, it has the side effect of turning off the red light in the headphone jack and allowing access to the internal speaks. I am not sure if this will work in the same way for everyone, but it has been a welcome benefit to a program that has numerous uses. Hope this helps.