Does the position without a fuse have any wires connected? It could be that it is a spare for options that are not fitted to your car. My 190E had only one fuse in that fuse box. The second one was vacant without any wires connected. It turned out to be a very neat way of fitting a fuse for my additional driving lights.

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107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.