One problem related to ignition module has been reported for the 2007 Ford Mustang. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2007 Ford Mustang based on all problems reported for the 2007 Mustang.
I was driving on the highway at approximately 60 mph. Without any warning the horn started blowing. It startled me and the drivers of several of the automobiles near me. Apparently, other drivers thought there was some emergency. I took the next available exit from the highway and pulled over at a safe place. I turned the ignition off and the horn stopped blowing. I started the car and pulled onto the street and the horn again started blowing. After stopping and starting again, the horn stopped blowing. The next day I took the car to the Ford dealer. They indicated that everything was "working properly at this time". They said that the "most common part failure is the drivers side module to start. " the price quote was $1058. 48 to replace the air bag module. I have removed the horn relay temporarily, but I am fearful that possibly the air bag will deploy while I'm driving. It would seem that in any case, this is a dangerous situation. I would be interested in knowing if this is a problem for others and what if anything I should do about this.