I bought this house 3 years ago with the sprinkler system already
installed, so I don't know much about it. It has worked for the last
few years. Now when I run station #2 another station (#3) always
comes on with it. When I run station #3 it runs by itself and station
#2 remains off. All other stations run as expected. I do not know
where to begin troubleshooting. Please help with your ideas.

Thanks,
Aaron