[JessHerbst]

 Took my bike for annual safety inspection yesterday, something Texas has always required but will stop next year.

 Bike passed all lights etc, then got to horn. Bike is not running but key is on. Press button and small ‘click’ from horns but no ‘honk’. Repeat a few times with same results.
 Start engine and try again and get full ‘honk’.
 Voltmeter shows 12.4v with engine off, 13.9v engine running.
The horns are Hella S90 using factory wiring.
With the key ‘on’ the bike is powering all the factory stuff plus a DVR & 2 cameras, an Indimate Bluetooth indicator device, charging mount for Beeline & analog voltmeter. All from the AUX circuit.
 
 I have ordered a relay harness and plan to run the horns direct off the battery with the horn circuit triggering the relay. Hopefully it will resolve the issue.

 Anyone else seen anything like this?

[NVDucati]

Took my bike for annual safety inspection yesterday, something Texas has always required but will stop next year.

 Bike passed all lights etc, then got to horn. Bike is not running but key is on. Press button and small ‘click’ from horns but no ‘honk’. Repeat a few times with same results.
 Start engine and try again and get full ‘honk’.
 Voltmeter shows 12.4v with engine off, 13.9v engine running.
The horns are Hella S90 using factory wiring.
With the key ‘on’ the bike is powering all the factory stuff plus a DVR & 2 cameras, an Indimate Bluetooth indicator device, charging mount for Beeline & analog voltmeter. All from the AUX circuit.
 
 I have ordered a relay harness and plan to run the horns direct off the battery with the horn circuit triggering the relay. Hopefully it will resolve the issue.

 Anyone else seen anything like this?

I can't speak to that specific horn but some need to satisfy the initial"in-rush" voltage. With your luck it will be 12.5v
If you don't need it to sound while not running ... do nothing. Else, wire away.