You will be stopped at the Lukeville crossing by the Americans who will ask out about weapons, how much money you have etc.
On the Mexican side, you will pull up and either get the red light or the green light. If you get the red light, you could be pulled over for an inspection. That is usually a open the door, guy comes in and looks around. If you have a pet, they might ask for proof of rabies shots. I would have a copy ready to give to the inspector.
This is what happened on our trip down last year but it has been a little different every year for the last 8 years.
Going through the Mexican side, stay at the line and wait until the rig ahead of you clears the inspection area before proceeding. A group ahead of us were real close to each other, I guess he thought he would get lost unless he was right on the tail of the one ahead. Anyway, he was told to back up and with a toad, he created a mess.
Also do not speed when going through Sonoyta and come to a complete stop at the stop signs. Observe the speed limits way out of town also.
