the car continues to offer fun surprises. The latest is you have to try and out a seat belt on your dog in the back seat if they weigh over 50lbs or the seat belt alert will chime. That was a fun Saturday am.
So, I believe the sensor is in the middle of the seat or thereabouts. When you use a booster or a car seat, it doesn't trigger the sensor because there isn't a consistent pressure against the sensor where the derriere would be located. Saw this happen yesterday when my son unbuckled his sister's car seat and the sensor didn't register until her seat slid over a little and engaged the sensor.
That sucks. Most likely needs the HV battery and Wunderbox replaced. Post-replacement, I’ve never heard of anyone having any issues with it (myself included). Good luck!