My 2002 ford F250 only clicks when I try to start it. I charged the batteries, but it still just clicks?

My 2002 ford F250 only clicks when I try to start it. I charged the batteries, but it still just clicks?

Big Fords are famous for corroding the INSIDE of the positive ( red wire ) battery cable clamp. So pull that clamp off the battery post & scrape both the INSIDE of the clamp & the sides of the post with a small pocket knife blade. If that helps, most all car parts stores carry a small wire brush designed just for that task. Also around '02, Ford tried a 'sheet metal' battery post clamp instead of the old fashioned lump-of-lead clamps. They didn't work. So if your truck has those 'light weight' clamps, there's nothing you can do except replace them with a pair of heavier lead clamps.

Likely the starter, also check wiring to the starter & the battery post where the starter wire is attached. It may look tight, but check it. I had a car that did the same, I replaced the battery, then starter, only to find a loose wire that looked tight, but wasn't, after tightening it all was well. So I ended up leaving the new parts on, wasn't going to do the work again, and knowing they will be good for a few years.

Put the headlights ON and try to start it. If the lights go out after the click it will confirm a loose or corroded connection to the battery. Also check your GROUNDS. If the lights stay bright after the click you have an open circuit to the starter motor. Meaning a starter relay or solenoid is not sending the signal to the starter.