I don't know very much about electric carts, but I have a little bit... just a little bit... of experience on this,
This is what your regen speed sensor should look like... (Less the ripped out plug)
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5 years ago I worked on the first cart I owned, a 98 48V Regen 2 that had a catastrophic U bolt failure. (owned by someone else at the time)
Remember this mrgolf?
http://www.buggiesgonewild.com/elect...-sparkies.html
I bought my replacement speed sensor from David @ Revolution Golf Cars,
I remember at the time that they were somewhat hard to find, but David just happened to have access of one for me!
What concerns me is... your using a regen 1 motor on an IQ platform...
I'm not sure that the old style regen speed sensor will be compatible with an IQ controller!
I'd give him a call, or send him an email and see what he has to say!
https://www.revolutiongolfcars.com/