Pressing Locking Rear Axle button while doing 80 mph

[Efrain]

Today, while doing 80 mph on the highway, I accidentally pressed the Locking Rear Axle button on top. A light went on and I kept pressing it again but the light didn't want to go off. After a while it did by itself. Does anyone out there know if there are any dire consequences to this?
Around the same time I heard a popping sound like a rock hitting my undercarriage and there was a smell like a lighted firecracker. Was this just a coincidence (I hope so) or did some thing happen down there? The car seems to work fine and all gauges measured normal.
I would really appreciate your comments on this.