Why is my A32 not vibrating

Your phone, like all modern smartphones, has a small motor with a counterweight that causes the phone to vibrate when the motor is activated. If that motor fails, the vibrate function on your phone will no longer work.

While there could be other causes, the motor is the most likely cause. You'll need to remove the motherboard in order to check or replace the motor; it's possible the glue holding it in place has failed and let the contacts move out of position, so that's something to check. I'd have a replacement motor on hand though; it's not likely to be very expensive. Here's a guide from the French site SOSav showing how to do the job.

Vibrator Galaxy a32 repair - Free guide - SOSav

Good luck; let us know what you find!