The relay of C180 is locate at the front near the brake servo in cover with black top.
on my Mercedes c180 2002 the spare fuses are found with the spare wheel in the boot in a tool kit.
Did you check the boot, beside spare wheel?
check inside the front fuse box lid for discription. it should be number 14
relay is in fuse box, near break booster, fan switch is in left front of the intake, blue sensor has two pin.
its in the engine fuse box on the drivers side . Looking in from the side of the car it is on the bottom right. fuse 64 10amp red.
You can find a Mercedes-Benz 180 fuse layout diagram in the back of the owners manual. You can also find the fuse diagram on the inside cover of the fuse box.
The fuse for the cigarette lighter on a C180 Coupe is No 47, a 15 amp (blue) fuse located in the fusebox in the back of the engine bay.
under the rear seat try the fuel pump relay first, in the boot in the fuse fuse box top one or first one
Did you by any chance make a spark removing that battery? If you did or didnt I suggest you check the fuse
Check in the fuse box
It is underneath a black cover that is behind where all the fuses are located(drivers side near the power brake booster on the firewall). You need to remove the six screws holding it in place. The fan relay is the relay with the 30amp fuse in it. If your fans are not working this fuse may just need to be replaced and not the entire relay. It is very easy to get to once the cover is removed. Good luck
In the trunk