A few turn up in a simple Google search.
None appear to be an exact substitute.
One cannot accept a supply as high as 12V.
Another only puts out pulses of 0.4 V amplitude. Etc.
Examples:
https://www.newark.com/honeywell-s-c/ss49/ic-hall-effect-sensor-to-92-3/dp/95F5207
https://www.newark.com/honeywell-s-...J1786?in_merch=true&MER=ALT_N_L5_Sensors_None
The above do not appear suitable.
Here's a roundup describing various types:
https://sensing.honeywell.com/index.php/ci_id/54924/la_id/1/document/1/re_id/0
There are many mail-order electronics houses where you can look over a variety of hall effect switches. Example, Mouser, Jameco, Digi-Key.
Typical price is a dollar or two. They charge several dollars to ship just a few items.
If you are willing to experiment, then you might purchase a few. Look for a unipolar non-latching hall switch which can take 12V supply.
Internally it may need a pullup resistor so that it will produce 5V pulses.
It would help if you could verify whether the board receives a 12V supply, or a 5V supply. A meter reading at a couple of spots should tell you.
Since the board has few components, it would pay you to make sure something else isn't causing the breakdown.
Did you examine for cracks in traces and solder joints (using a magnifier)? It's a location which gets heavy vibration.
Also are the diodes zener type? If so then it will help determine what specs apply to the hall switch.