The issues I have w/ the Kahlenberg horn wiring diagram are that the solenoid switch is not shown as fused and there aren't snubber diodes shown.
The solenoid switch needs to connect to a fuse / circuit breaker protected 12 VDC feed. If connected to a fuse, double the rated current of the solenoid. It should also be okay to hook it to the protected side of the circuit breaker.
The solenoid and the motor will create an inductive voltage kick when de-energized. That will cause contact corrosion. The contacts may be protected by adding snubber diodes, w/ the cathode to the positive side of the load contact and the anode to ground.
Did you go w/ the whole Kahlenberg kit, or just their horn?
The solenoid switch needs to connect to a fuse / circuit breaker protected 12 VDC feed. If connected to a fuse, double the rated current of the solenoid. It should also be okay to hook it to the protected side of the circuit breaker.
The solenoid and the motor will create an inductive voltage kick when de-energized. That will cause contact corrosion. The contacts may be protected by adding snubber diodes, w/ the cathode to the positive side of the load contact and the anode to ground.
Did you go w/ the whole Kahlenberg kit, or just their horn?