Pag naka relay kahit wag nang gumamit ng fuse. Pero okay lang naman mag fuse. Ilagay mo inbetween sa #30 ng relay papuntang positive terminal ng battery.
Roots and Bosch are both the same, even OEM for Merc is made by Roots in Mercedes branded shell. Bosch haven’t R&D Center they buy from roots and sell it by own branding... roots is a good brand it made world class horn so no doubt... you chose booth products blindly