I know it's a year later if I saw the date right. Are the ants in question rasberry crazy ants, or fire ants.
rasberry crazy ants are a pain. They invaded Houstons NASA grounds over the last few years.
They take out my well 3 times a year. Well I tries silicon last year. It wo rked for a long time but the problem is then moisture builds up over time a nd takes out the points. lol I did keep my well going for a year this time. So I will deal with once a year changing of points the 3 times a year.
Seal the bottom holes of the switch box. Seal the hole between the switch box and the pump but not to much or you will mess with the stuff in the pu mp. You just want to block the hole. Seal around the bottom edge with silic on on the switch box. Put the cap on and tighten down. Put silicon where yo ur wires come into the box on the side. Do not get any silicon on the point s during the sealing. Good luck!!!!!
If it's the same ants, this problem has been seen as far north of Dallas.
Good luck. I'm still looking for a better fix to the problem.