Welcome aboard Coyote!!
If you're referring to the speedometer guage, that is manufactured by Faria Instruments:
Do you still have the gauge? What is wrong with it?
Faria has a limited-lifetime warranty on their gauges. They will often replace it for a nominal replacement fee. (Hence limited).
You may want to contact them directly to see if it can be repaired/replaced.
If it is simply not working, that is common. It works on water pressure from the pitot tube, which often gets clogged. They are inaccurate and you'd be better off referencing a GPS than a speedo. Speedo's don't record speeds accurately, particularly when running with or against tides or current. (With returns slower than actual speeds, while against typically shows faster than actual speeds).
Just a few thoughts.