I looked it up in the schematic diagram of the Illumination Board but the immediate power mosfet driver is under some epoxy, the only closest connection to that mosfet gate is 1 or 2 voltage translator (smaller mosfet transistors) back, on the 10th pin of the pin header J1, which is the signal "Illum_P".
This signal along with the 12th pin "Illum_N" seem to have the 40/60MHz signal that the array fires to sense and measure distances.
My hypotheses is enabling the array with pin 1 of the same J1 and then injecting a signal on illum_P and its negative inversion to illum_N.
What would be the best way to output a custom external signal through the array, if access to the power mosfet is blocked by the epoxy?