Insert the spade connector into the lower pin for fuse #3
Insert one “foot” of the electric windows fuse into the spade terminal of the cable
Insert the other “foot” in one of the spare fuse holders on the left of the fuse box. (I used the lowest fuse holder so that the cable can be as short as possible).
I tried different spare fuse spots, and all of which I tested worked. But it could be that not all of them provide permanent live.
Once the fuse is connected, try out your electric windows with the ignition turned off.
If your windows don’t work, check if you followed all steps properly.
If everything works as expected, tape the cable to the fuse box to ensure it’s not getting pulled out accidentally.
You can now shut your windows, even if you turned of your Smart’s engine without turning the key to the 1 position again.
This solution is inexpensive, saves on gas and is convenient.