Is the automatic function in the switch, the motor or both?

What would have to be done to make all 4 windows auto up and down?

 

all 4 don't on the GE?

 

The logic for the Auto up/down is probably done by a microprocessor or ASIC somewhere in the vehicle. Additional hardware would involve an overcurrent sensor in the motor leads (or a position encoder) - this is how the window "auto up" aborts if you put your hand between the window and the top of the window frame. Assuming the other 3 windows have similar hardware, it's likely a re-programming of the firmware would give auto functions to those windows.

My guess is the other 3 windows don't have that extra hardware, to save cost and test time.