When I select my Forerunner 235 under Available Devices on my new phone, it says "Bluetooth pairing request", and I must enter PIN number. It says "usually 0000 or 1234". I tried those and known PIN numbers I use, and NONE of them work. So what do I do now to connect???
You shouldn't have to just "try" any PIN's. It should be visible on the watch if you're in pairing mode on the watch.
Maybe I'm missing something. Just to make sure, you do need to do the Bluetooth setup from the Garmin Connect Mobile app, not from the Bluetooth settings on your phone.
Pairing Your Smartphone
Suggest contacting Garmin support by phone.