I left my lights on at school! and my alarm was set! my car keeps going off and the alarm is not making the sound is usually does its a dei does anyone know what i can do?
If it is making a very muffled sound, like a sock in the siren, then your batter voltage is probally below the 10.5-11 volts needed for it to operate properly. Your car will still run with the alternator, but when its sitting still, the battery just does not have enough juice. Definitely time for a new battery or charge.
you have a bad brake master cylinder
