Audio jack problem, no speaker sound, red light

The red light in the headphone jack means that the MacBook Pro thinks that an optical audio cable is plugged into the port. Try unplugging and replugging a headphone plug into the port several times. There is a tiny sensor inside the port that determines whether the port operates in optical or analog mode. Plugging something analog in should trigger the sensor and restore the analog signal.

just press shift+control+alt+Power button and the headphone will be corrected ...the red light will go...no need of any apparatus ..

"just had the same problem RIGHT NOW - i took an air duster can (those pressurized cans that are made for dusting computer components) and i blasted the headphone jack....worked like a charm...i guess there was some dust or debris in there that got in the way and confused the computer's jack....i would suggest trying THIS method before sticking anything INTO the jack or blowing with your mouth (in fact, with all due respect, DON'T blow with your mouth...saliva will get in and RUIN the jack and sticking a screwdriver into the jack will only work against you, imho)

all the best!"

"The Apple 3.5mm headphone jack may have multiple different failure modes, since it contains 4 equally flimsy electrical contacts. Staring into the glowing red Cylon eye, they are: 2 ""sleeve"" contacts (nearest you), one at 9 o'clock and one at 3 o'clock (positions on an imaginary 12-hour analog clock dial); 1 ""ring"" contact (farther in) at 12 o'clock; and 1 ""tip"" contact (all the way in) also at 3 o'clock.

The one plaguing my Late 2006 MacBook is the tip contact. Tugging on it with a bent-tipped safety pin while watching through a magnifying glass works, but only until the next time I unplug the headphones, and so is too impractical. Jostling it with things like air, suction, Q-Tips, toothpicks, ballpoint pen inserts works for some, but not for me. What works for me 100% of the time is inserting a 1/8"" metal rod all the way and then dragging it out while applying moderate pressure in the 9 o'clock direction (towards the MagSafe connector). There is no problem using metal, even powered on, because headphone circuitry supplies no power and is protected against short circuits and static electricity. Just be gentle.

The shank end of a 1/8"" drill bit works well, and burying the business end in a bottle cork prevents it from cutting you (it is sharp). But I settled on a piece of nail, snipped down to an inch and filed slightly rounded. As a bonus, it fits into the little plastic clip on the MagSafe cable so it is always handy."

This seems to be a fairly common problem. There is another thread about it here.

"Put a screwdriver into the jack... you will feel a little piece of metal. Try to open that piece with your MacBook turned on, music on... and you will hear the sound when the piece of metal has in the correct place.

IT'S VERY EASY. I made that in less of a minute.

Sry for my english, i hope can help. Cheers!"