Ford Repair: 92 Explorer Starter Problem, starter solenoid, auto parts stores

Question
I have a 92 Explorer that will not start.  When I turn the ignition there is a single "click" and then nothing.  I had a buddy listen when I turned it and he said the clicking was coming from a small round (2 inches in diameter) part on the side wall next to the battery that the positive battery wire is connected to.  It seems as though the power to the charger runs through this part.  The battery is good but the starter doesn't seem to be getting any power.  I have a Chilton's manual but can't figure out what this part is or if it could be the problem.  Do you know what this is and is it possible that it is preventing power from getting the starter?  Do you have any other suggestions?  I appreciate any pointers you can give.  Thanks a lot!!

Answer
Bob,

Yes the part you describe is a starter solenoid. It supplies power to the starter itself so yes it will cause the vehicle not to start. They are pretty cheap and available at all auto parts stores. Disconnect the battery first then you can change it out.