Just closing out this topic, I took the plunge on
this extender and found that it fits and works perfectly. I can leave it plugged in and that's enough to activate the driver's seat and steering wheel heater during a remote start. It makes a big difference in the winter. I doubt that it would also work for the passenger seat because that uses additional electronics to detect a passenger. But I'd be interested to know if this also works for LCI models with factory remote start.