It won't start: new battery, have lights, it just clicks when you turn the ignition switch

That wouldn't be a computer problem , maybe be the ignition switch . If you don't know how to test automotive electrical circuits , viewing wiring diagrams an using a DVOM - digital volt ohmmeter your best bet , have a qualified repair shop check it out . More then likely just a electrical connection problem , Voltage drop testing on main power circuit's is what needs to be done.
Free wiring diagrams here http://www.bbbind.com/free-tsb/ Enter vehicle info. year , make , model an engine . Under system click on electrical distribution , then under subsystem click on power distribution . Click the search button then the blue link. Start at the beginning testing battery connections , cables . Power supply to the fuse boxes ,to the ignition switch , an from the ignition switch. There is battery voltage to the ignition switch ,hooking up a test light or voltmeter to that main battery power feed an turning the key to run start etc... does the light go out or stay bright ?
Check out put from the ignition switch , start , run circuit's
https://www.youtube.com/watch?v=SO-eKuhCOqc

https://www.youtube.com/watch?v=efKoWifdcag

hi Roy.
The starter won't crank. If nothing happens when you turn the ignition key to the "Start" position, it means that the starter motor doesn't turn over the engine. Most commonly this could be caused by a dead battery; here is How to check the battery. ... The ignition switch could be bad - it's a common problem.13 Aug 2013

Why a car won't start - troubleshooting tips - Samarins.com

How do you fix a car that won t start?
When your car responds with silence or clicking:

1. Turn on the car lights. ...
2. Tighten and clean the battery connections and try again. ...
3. Jump start the car.
4. If this works, immediately have the battery tested, especially if it's old. ...
5. Things could still be worse - such as a bad starter or alternator.

Car Won't Start? Here's What You Should Do ' GEICO

https://www.geico.com/more/driving/auto/auto-care/what-to-do-if-your-car-wont-start/ Search for: How do you fix a car that won t start?

check your battery and terminals first.... clean or replace as needed. After that check your fuses. After that if you arent comfortable with automotive work, take to a shop. Good luck!!!

many things will cause no start problems could have faulty ignition switch.use test light see if power going to starter if not check ignition fuse to starter.if power going to starter, more likely starter solenoid or starter faulty.if ignition fuse okay and starter and solenoid okay still no start problem could be in the ignition switch or inhibitor switch faulty.code scan for faulty theft security system which will also cause no start conditions.

We just went through this with our 2003 Rendevous. Clicking like crazy but wouldn't start. Replaced the starter but still doing the same thing. Our next step was going to be replace the battery (which tested well) and the ignition assembly. Out of frustration, I hit the top of the hood and the headlights came on!! Further investigaton proved that the problem was a corroded ground wire on the battery. Hope this helps

sounds like a bad solenoid on the starter. replace the 1999 starter(Its old).

Switch on head lights or cabin light. If they doesn't come on or is weak, the battery is flat. Ensure that you switch off the lights.
With ignition switched on, assuming the lights on the instrument panel cames on and your immobiliser is deactivated, turn ignition to start. You should hear the solenoid at the starter making a click sound. If not, the battery is flat or the starter solenoid is faulty. If it does make a click sound, the battery could be too low to turn the starter or the starter is faulty. Assuming the immobiliser is working correctly, and the starter tries to turn the engine but it doesn't want to turn, the gasket could be blown and the cylinder filled with water, or the engine could be seized.
Hope it is not the last case. MarioCpt

Faulty ignition switch lock cylinder.

Is the ignition switch good? If the starter/solenoid; starter relay, battery and cables are all good that is about the only thing left.

Do you hear a click when you turn the switch?

Hi, if the car engine fails to crank, there is a fault in one of the components in the battery/ignition/starter circuit. Low battery (Check battery voltage, recharge if low, or jump start with another vehicle or battery charger). Bad starter relay/solenoid (Check for voltage at relay, if relay has voltage but there is no "click" when key is turned to start, replace relay). Bad ignition switch (Check to see if voltage reaches starter relay/solenoid when turn to start. If not, check for open P/N switch and brake or clutch pedal switch. Replace ignition switch if defective).