I'm looking into the Hella Twin Supertone Horns. They look kinda like oem but red. It does come with a relay but is it required? Couldn't you just replace the oem units and be done? I'm assuming the oem units have a relay connected to them already.

 

From what I heard, some people just used the oem wire and changed out the fuse with a higher rated one. The problem with newer honda is that the horn now shares a fuse block with the brake lights. The correct way would be to have it installed with a relay and it's own fuse.

 

The Helms manual states that fuse #47 supplies the ABS modulator unit, Brake lights, Cruise control unit, ECM, High mount brake light, Horns(s) for all model years. The only stated difference between the models are: '00-01 models have a 10 A fuse and '02-03 models have a 15 A fuse (the later models have two horns instead of one). So, anyway, it seems that the only change is a larger fuse (by 5 amps) for the extra horn.