Had the same issue with my 190e.
In my case, it was the electromagentic clutch.
The sensor does not cause a short coz it is only a switch that closes when the temp. reaches like 107 deg C or something (i forgot) and supplies 12V to the electromagnetic clutch.
You can test by applying 12V to the wire going to the clutch.The ground for the clutch is already connected somewhere below the air cleaner housing.
The clutch should CLICK upon applying 12V.If it doesn't, it's fried, and that causes fuse #10 to blow when it is connected back to the circuit.
If i remember correctly, it blows as soon as you turn the key.
You could look at my earlier posts in which I was hunting like crazy for the short, which turned out to be the clutch.
Good luck and let us know your findings.
Babybenz 1991 190e 1.8