As Chris R said.
Find the black push button usually located under the sterring wheel close to where all the fuses are. Ask who installed it in for the location if you can't find it.
then.
Its a combination to turn this mode off. you have to first unlock the car, start the car then when you turn off the car quickly press and hold this button for few seconds.
or
when the car is started then hold and press this button. then when you turn off the car and close the doors you should see your blue led flashing back to normal and sound will come back on.
Just try the combos out. Every now again i got to do this as when i take to mechanics (weeks on end) i turn this auto lock off auto wind up windows cause they don't understand to take the keys out or they will be locked in the car.