Originally Posted by beechum1
Ultimately aren't we just trying to keep any feedback from going to the other unit and giving a false signal? A diode on each "+" after the split?
Indeed, that's exactly what you're after (like I said, same principle as with the buttons). What you need to do is, once you splice to connector (or leave it alone and use an opposite connector) check which of the 2 wires is signal (should be high at around 3-5V) and which is GND. Connect both signals together each with a diode (anodes to the signal line, cathodes together meet with the one line of the sensor). The 2 GNDs and the other end of the sensor all come together then!