Ford Repair: 1992 F-150, starter solenoid, proper voltage

Question
Hey Mark,
I have a '92 F-150 with a 5.8L V8.  It has about 110,000 miles on it.  My problem is with the ignition system.  Recently, when I tried to start it, I got one "click" from the starter solenoid.  After that, I replaced the battery, solenoid, and finally the starter itself.  It's been about a week now, and I'm back to the one "click" from the solenoid when I try to start it.  I've tried jumping it off and sparking the solenoid, but nothing worked.  What could be my problem here, and what would you recommend I do?
Thanks for the help,
Ed

Answer
first make sure your cables are of good quality-clean and tight we get more vehicles towed in for no crank because of connections than you would believe-also more batteries are replaced unnecessarily for the same reason-if cables are tight and clean at battery/solenoid/block and starter then you need to make sure you are getting proper voltage through them. also you need to make sure you are getting a good signal at solenoid from ignition switch small elbow wire-if you bought any of your electrical components based on price or from az you may be doing it again i don't and will not buy anything electrical from them what am i saying i don't buy anything from them. if all is good then have it checked out so you don't waste money replacing good parts chances are you did not need all those parts already. good luck.