The potentiometer is the way to go. The yellow wire is the sensitivity line. Open and the sensor is at its least sensitive grounded is its most sensitive. Pot is I believe a 1 megaohm. Wire one end to the wire and the wiper to ground. It takes some time to get it right. BTW; I believe the the installation guide says to bury the wand 2ft in the ground. The way the wand works is it measures the ground inductance and is very sensitive. I've got the same problem but in reverse. My truck won't set it off but a larger truck will. If I set the sensitivity higher it will open on it's own without a vehicle present. Good luck.