Replace fuse #5. At the very least remove and replace the old fuse. Don't just give it a visual inpsection.
The fuse box is in the engine compartment ahead of the brake master cylinder (US spec cars, anyway). Flip the tab forward and lift the lid from the front.
If it didn't occur to you to check the fuses right away, replace all the fuses. The type of fuse MB uses in these cars deteriorates over time. 12 years is a long life for these fuses. It'll cost you less than $5 to get all the fuses you need from FastLane.