KZ1000J Horn Electrical Probelm

Have the dual stock horn setup and it is not getting the correct voltage for running both horns Works just fine with either single horn plugged in but when both connected goes to 1/3 the volume According to the manual there should be 25vdc and I am only getting 12vdc My shop manual shows no relay and the wiring shows no shorts I have tried using other horns and to no avail........ I am missing something which my shop manual isn't telling me All other electrical on the bike is 100% fine an just need some direction on where to troubleshoot and if there is a relay that bumps the voltage to 25vdc where the heck is it???"?? There has to be some sort of transformer to double the 12vdc system Thanks

That is the first I've ever heard of a voltage multiplier/increaser on a Kz.

Do you happen to have a wiring diagram for your bike, or a link to one?
Or do you know what year or full-model designation you have?

All of the diagrams I can find for Kz1000/1100 with dual horns just have a normal wiring where both horns are in parallel and simply run off one button on the ground side.

Horns do take a huge amount of power so if there is any weakness in the electrical system, a horn will usually expose it.

He might be misreading the manual which says to set the voltmeter to the 25V DC range & it says there should be battery voltage.

Some of his connetions at the wire plugs or horn switch Botton assy could burnd or corroded. Under low current load (unpluged horns) he will read 12 Volt, but under heavy current load (horns pluged) he will get a voltage drop. OHM´S law: U(Volt) = R(Resistend Ohm) * I (Current). If R on a bad wire/connector/switch will get high due to the low cross-section (heat) will drop I (current) both horns need to work.

With aftermarket horns that draw considerably more power than the stock ones, a relay and dedicated wiring to the horns is used to avoid overloading the button. I wonder if somebody installed some high power horns without the relay?