How to replace the battery?

They use many, so the answer is always "the same as the one that came out of it".

https://www.energizer.com/specialty-battery-finder/bulova-watch-battery-replacement

Nothing here, which is odd because that normally works,

https://www.google.com/search?q=Bulova+98H48+battery+type

Look for tiny engraving next to the battery compartment.

Or ask them direct.

https://www.bulova.com/ca/en/contact-us.html

..

It sounds like there is a short somewhere, or the Indiglo function is permanently on.
I suggest you look inside the case and check the movement and how the battery was installed and see if anything looks wrong.
If you can find nothing amiss I suggest you take it to a jewellers or similar that does battery replacements and let them work it out.
Hope this helps.

Do a reset, better yet have a watchmaker do a reset.

I have found the instructions on their web site but this alarm is not mentioned.

I suspect that it is a battery low indication; this would be consistent with a battery that is over a year old .

Try having the battery replaced.

You have to check if the digital part has separate battery. It is quite common to have two batteries in one watch - one for each movement. If this is the case, replace battery. If there is only one battery for the whole watch, you will need watchmakers help to rectify the fault.

Take your watch to your nearest watch shop and ask them to do it for you.

You can get into difficulty replacing batteries and it is not worth the risk for
the small cost saving in doing it yourself.

Fading display is sign of a weak battery. You have to replace the battery and everything will be back to normal. Rate me, plz.

If you haven't already done so, try replacing the battery.

You can remove the battery cover with a small coin, check the type (all batteries are marked) and buy a replacement.

Good luck!

On most casio watch you can see AC (all clear) point , youy need to resset clock connecting this point with + on battery about 5 sec.

I have same problem but on my watch I do not see AC point. :)

regards
ststefan