Beats me.
We had a war with Mexico back in the 1800s.
And more recently, Argentina had that spat with Britain over the Falklands.
But other than that, I can't think of any wars that Central or South American countries have had with each other.
Oh, they've had plenty of revolutions, civil wars and insurgencies, such as when Panama gained independence from Colombia, or the guerrilla war they had in Nicaragua. But I don't think I can come up with any actual military conflicts between two established and somewhat stable nations.
I could be wrong.