Each fuse protects a certain electrical circuit in the system and come in a range of different ampages. Each ampage is noted by a specific colour code that is used worldwide.
3 Amp Violet
4 Amp Pink
5 Amp Tan
7.5 Amp Brown
10 Amp Red
15 Amp Blue
20 Amp Yellow
25 Amp White AKA Neutral or Clear
30 Amp Green
40 Amp Orange
50 Amp Red
It should also be noted that car fuses come in different physical sizes, the smart has 3.
Mini blade fuses are used in positions 5 to 27 on the fuse box.
Standard blade fuses are used in positions 1 to 4 and 28 to 31.
Maxi blade fuses are used in positions 32 to 35.
Positions 32 to 35 are on the unseen top side of the fuse box and they can only be accessed by removing the dash or pulling the fuse box from it's mountings in the footwell.
Standard blade fuses are also used in positions R1 to R9 which are also known as positions 36 to 44 which are on the right hand edge of the SAM unit. Half the fuse is held by the SAM unit, the other half floats free to the side where a spade connector can be connected.
In a standard car these spaces would be empty and are used as an aux power source
for optional extras such as heated seats. These can be used for what ever you wish.
Mini blade fuses are used in positions 1 to 20 on the fuse box
Standard blade fuses are used in positions 1 to 4 and 21 to 26.
Maxi blade fuses are used in position 27.