There could be several reasons why your iPhone is not vibrating when on Silent mode. Here are some possible solutions to try:
1. Check vibration settings: Go to Settings > Sounds & Haptics and make sure that both “Vibrate on Ring” and “Vibrate on Silent” options are enabled. If either of these options is disabled, toggle them on.
2. Restart your iPhone: Sometimes, a simple restart can resolve minor software issues. To restart your iPhone, press and hold the power button until the “slide to power off” slider appears. Slide it to power off your device, then press and hold the power button again until the Apple logo appears.
3. Test vibration with Silent switch: Flip the Silent switch on the side of your iPhone on and off a few times. Check if the vibration works when the switch is in the Silent (orange) position and when it is in the Ring (no orange) position. If it works in one position but not the other, it could be a hardware issue with the switch itself.
4. Disable Do Not Disturb: If Do Not Disturb is enabled, it will silence all incoming notifications and calls, including vibrations. To check if Do Not Disturb is turned on, swipe down from the top-right corner of the screen to open Control Center. If the crescent moon icon is highlighted, tap it to disable Do Not Disturb.
5. Check for software updates: Outdated software can sometimes cause unexpected issues. Make sure your iPhone is running the latest version of iOS by going to Settings > General > Software Update. If an update is available, tap Download and Install.
6. Reset all settings: If none of the above solutions work, you can try resetting all settings on your iPhone. This will not erase your data, but it will revert all settings back to their default values. Go to Settings > General > Reset > Reset All Settings. Enter your passcode and confirm the reset.
If none of these solutions solve the issue, it may be a hardware problem. In that case, you may need to contact Apple Support or visit an authorized service provider for further assistance.