In short, the cruise control on the FB used a speed sensor on the speedometer. a signal is sent out from the cruise control box and ran through the "vehicle speed switch" . It would seem that selecting the Vehicle Speed Input using a DPI with the main source as Drive Train Sensor with Edge Select as Falling and calibrated at the Mazda 1024 pulses@ 60 MPH would provide the ECU with a signal.

That is at least my theory.

 

should work i have one toyota wire like that and work