I have the same problem with my text messages not vibrating. I went into the settings on the messaging options and am certain that I have it selected to vibrate when messages are received. Even when the phone is on vibrate only it still will not work. This is very frustrating for me, as I have to have my phone on vibrate a lot and have been missing many of texts because of this.
Hey, i posted this about 3 days ago in dif forum and got the same type of answers, I was not able to make my texts or emails vibrate. I got Handcent app and had many more options and settings but still no fix.
so stopped at the Sprint Repair center and they said they would have to do a factory reset. the vibrate was working when I used the volume switch down to vibrate so they figured is not the cell but some firmware. I told them I would back the next day I just needed a day to make sure my stuff loaded so far to the cell was not lost.
next day in the morning I said to my self, wait I can do the factory reset and save time and trip.
Did it and the text and email vibrate works fine like is supposed to do, all I had to do later was just get all the apps back from the market.
You don't need to hard reset to make it vibrate. Mine was doing the same thing until I found out that when you turn down the ringer all the way it puts it on silence. Well if you hit it one more time it will go into vibrate mode. Problem fix.