the stock benz horn on c220 and c280 is low pitched. i wanted to install a louder horn. pep boys has some generic airhorns. it says simple installation, just connect the two wires to the existing horn's wires. anyone know where these wires are and how i can connect them? anyone done this themselves? do all pepboys horns work on a w202 mercedes? i searched the forum but there were no guides on this horn instiallation