My 2004 Ford Taurus will not turn over... my battery checks out good, have cleaned and tightened wires, all lights come on. Just a click and then nothing when I turn the key. Will not even jump start.

Any clues?

If all the lights come on, it's not your alternator, which is good. Must be the starter.

If all the lights come on, it's not your alternator, which is good. Must be the starter.

Thanks!

Remove and fully charge or replace the battery. Most auto parts stores will test and charge batteries for free. It may be that one or more cells in the battery are bad. Common problem in hot weather. My bet is that replacing the battery will solve the problem. If you buy a new battery, charge it before installation.

If the problem persists, focus on the starter solenoid. They are easy to replace and normally the motor is fine. It may save you money and the hassle of removing and installing the starter motor, which can be a pain if you have the Duratec engine:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-9.html#post3204098