Strip a bit of the sheath from the cable and crimp or solder the spade connector
to the wire, if you have any I recommend using heat shrink at the base of the connector.
Slide another bit of heat shrink on, strip a bit of sheath from the cable and crimp or solder
the spade terminal to the other end. Heat both heat shrink tubes over the bases of each.
Remove the 30A fuse from position 4, the diagram can be seen
Slide the terminal onto 1 leg of the fuse and the part is ready to be fitted.
Find your SAM unit, it's the fuse box in the footwell:
Left hand side for all for2s,
Driver's side for all Roadsters,
All the fuses are numbered, take a pair of pliers and remove fuse 4.
Insert the spade connector into the furthest side of the hole (next to the number 4)
The fuse you removed should be plugged into the spade terminal of your wire.
With that done you can now push the fuse into any one of the furthest five side holes.
These are labled R5 to R9. All 5 ports give a constant voltage.
With it all in place, sellotape the wire to the SAM unit to stop it getting snagged.
Give it a test. Keep the ignition off and test the window buttons.
If it doesn't work, you have done something wrong. Double check everything.
If you plug it all in and the blower motor starts spinning, you have put
the spade terminal in the wrong side, if nothing happens check the fuse and position.
Thanks to Sacki for pointing out the error in my fitting. It is now fixed.
Same idea applies but you will have to do the research as I have never done this on a 600.
Firstly, the 600cc smart doesn't have auxiliary fuse ports so you will have to use an existing one.
If you find a permanent live fuse you can use a bypass connector (sometimes called a bypass fuse).
You then just have to remove fuse 24 and place it in the bypass connector.
Attach a spade connector to the trailing wire and push it into the place where fuse 24 came from.
New Smart Fortwo 451
Thanks to Ed Messner for letting me know that this works on the new smart 451.
The setup is almost exactly the same as before except it has a different fuse rating and
connects to fuse 3. Again, you must match the fuse rating that is currently in place.