SHOs have dual electric horns (high and low pitch, says EVTM). I am replacing mine. I'd like to know if the +12V wiring to the stock horns is stout enough for my new horn, or if I need to add a relay. This is in a 92 so the stock horns are on a relay in the first place. If I measure the ohms resistance across the old horns and the new, does Ohm's Law enable me to calculate the amps drawn? VO