Here's HOW TO-Why not just post the procedure so everyone can see...
TAKE OUT YOUR HEADLIGHT PODS WITHOUT REMOVING THE FRONT OF YOUR CAR, OR SIDESKIRTS:
You will first follow the excellent photos and description on Evilution and stop before removing the pictured bottom side torx 25 bolt at the Bottom of the fender as shown in the link below.
It is not necessary to remove the side skirts, or the turn signal repeater since the fender will not be coming off the car.
Thank YOU Kane very, very much for the Evilution Link that follows:
Evilution - Smart Car Encyclopaedia
I do remove all three screws including the one holding the retaining strap for the flap and the pins on each fender just below the innermost bottom edge of each head lamp. A tack puller is great for these pins.
Once you have worked your way down just prior to removing the fender bolt, the fender is now floppy loose and can be easily bowed out by hand since it is springy and highly flexible, so that a screw driver can be inserted to loosen the third screw beneath the rear of the headlight pod. If you scroll past the lower fender bolt location on the evilution site above, you will see the red circled locations of the pod bolts...
Unscrew, lift out the pods, and unplug. Piece of cake.
YOU now also have access to the wimpy horn. The Wolo Bad boy will mount on the original horn mount and plug right into the OEM connectors. AS always, orientation is important. You don't want your air horn gurgling or drowning. Wolo's are usually stocked by Harbor Freight. Nautilus compact truck horns are similar but have a singular 300 Hz. Deep voice. Perfect for tiny cars!
So, you have now removed the headlight pods, accessed the horn, and NOT had to completely denude the front of your car, NOT get a friend to help, NOT have had access to padding to place your fenders on so they don't get scratched on the pavement, NOT dealt with unplugging fog lights or Brabus air dams OR side skirts, NOT dealt with jacking the car, which means owning a jack so you could remove the wheel to gain access to the horn through the wheel well etc.
I do recommend protecting the fender from the screw driver when removing the bottom rear pod screw, and using a magnetic screw driver so you don't drop that pod screw. They are like marbles. They will always roll to the furtherest most unreachable location UNDER the piano. I always keep one of those handy so I know exactly where the dropped screws will be!