Horn no worky


Buick and AMG pilot
Jan 17, 2006
When horn is actuated, all I get is a clicking from a black box mounted under the dash. It's basically in line with the passenger remote mirror control. It has two plastic clips which allows access to a circuit board inside. What do I do now?
Mount this just outside your window. :eek: :D

Update: I have battery voltage on the green wire when the horn button is depressed. Upon release, voltage drops to zero. However, sometimes it "sticks" and battery voltage remains constant on the green wire until I tap the horn button again. I tried hotwiring both horns to the back of the alternator and got nothing. I'm at a loss.
The clicking behind the dash is the horn relay.

Since you wired to horns to the alternator terminal and got nothing, I'd say the horns are bad. Having both go bad is unusual. Note that the ground for the horns is via the mounting brackets to the fender. That could also be the issue.

What I did to diagnose mine was connect a test light to the connector that goes on the horn and see if it lights up when I hit the horn button. If it does, then you have a bad horn... or ground. It it does not light up, the problem is in the system...
UPDATE: Both horns were bad. I have no explanation why. I hadn't done any work on the car, much less disturbed that area under the hood. I hotwired and grounded each horn and still got nothing. I installed two new units (high and low note) and all is well. I'm here to attest that if it can break, I will manage to break it somehow.