So, as I'm getting on the highway this morning...
I start signalling left (lever is not locked in position), and gaining speed.
I hold down my cruise control 'on' button (let hand) simutaneously as I have the left signal still engaged.
Then I hit the 'coast' button (right hand controls), still 'on' the first two button/lever.
My horn sounds off
It kinda startled me, so the instant I release the 'coast' button (right hand) the horn stops.

I had a remote starter installed recently, nothing else ever done with the wiring.
That couldn't be the reason for the honk.
Will someone else please try hitting all three buttons simutaneously, and let me know if your horn sounds off, too?
Thanks.

 

I cant say I've seen this happen before. I tried it in my truck and everything worked just fine. I'm not an electrical guy at all but good luck!

 

wow good luck with that one

 

I'm just curious. What would cause someone to manually engage the left blinker without putting it in the lock position, then reach up and hold the cruise control on and also hit and hold the coast button... the whole time while accelerating. Theres a good possibility those functions have never been used before in that manner/order.