lower ac current from speedsensor
Instead of just 1 single resistor youll need a resistive divider: resistive dividers

If the input your connecting to isnt high impedance you may also need an opamp in a voltage follower configuration:

https://www.analogictips.com/voltage-follower-unity-gain-amplifier-voltage-divider-faq/

...This is of course assuming that the output voltage is proportional to speed and not something else like frequency