Horn Honking when accessory attached

[Zubicon]

When I attach my viair compressor to the battery via the alligator clips I’ll get a random honking of the horn. I first thought maybe It was a front radar issue but I turned that off, set the parking brake, tried with the door open and closed but it still happens. Anyone got a clue as to why I get this?

 

[Threesuns1]

If you're putting air in tires when hooking it up the horn will beep when tire pressure reach set pressure.