I replaced the battery terminal cable ends. Now the car will not start, There is a clicking noise from the starter.

Sounds like battery terminal corrosion. Try cleaning the terminals and cable ends with baking soda and water and an old toothbrush, then add some dielectric grease and put the cables back on. If that doesn't help- check for bad battery cables: https://getjerry.com/questions/how-do-i-test-if-my-battery-cables-are-bad
If that all checks out, then your N.E.W (Never Ever Works) starter is very likely defective. Your alternator looks good and 12.6 volts on a new battery is just fine.

• Okay, a clicking sound is the solenoid engaging the starter drive gear but the starting motor is not turning over. First possible is low battery. Second is bad or dirty connection, usually battery terminal. Good enough to energize solenoid but not enough amps to spin starter. Third is a bad starter motor, usually a brush corroded, worn or stuck.
• Lift the hood and look at the battery terminals. if they are clean and tight, check the battery for charge. I usually hook a booster on and try cranking the engine over. ZIf it works, charge or replace the battery.
• If it didn't crank, Take a jumper cable and connect the one end to the battery positive. Touch the other end to the starter motor terminal. Motor should turn over, if not, replace the starter.

CHECK FOR YOUR BATTERY POWER IF IS STRONG ENOUGH.ASK AN ELECTRICIAN TO DO THE JOB.

Check the starter. The clicking is caused by the starter solenoid engaging, but the starter not turning over. This will more than likely need to be replaced.

have someone turn key and you grab the battery cables and twist/ wiggle them and also pull upward on positive cable going to starter to see if it makes a better contact to start truck. I dont know who or how the starter got tested but normally if the starter just clicks it is either not enough power going to starter motor, or the starter selonoid is bad, or the starter motor is bad. so double check all cables and cable ends,and all cable contacting points. check battery for tight posts and connections.

Sounds like a flat battery, it will have enough power to kick in the starter solenoid [the clicking noise] but not enough to turn engine over. Best to fit a battery that you know is good into the vehicle. If the fault still persists the starter could be faulty. To check the starter bridge the main battery power terminal [30] on the starter solenoid and the smaller terminal [50] also on the solenoid [power from ignition switch]. The starter should turn. MAKE SURE VEHICLE IS IN NEUTRAL WHEN DOING THIS AND TAKE CARE NOT TO BRIDGE POWER CABLES TO STARTER HOUSING.

mware nailed the first thing to check but if the battery checks out OK, the next step would be to remove the battery terminals (always negative first) and clean the cable end and the battery's terminals. If this still doesn't help, you will have to trace the two cables to their other ends (one, the positive, will go to the starter itself) and thorougly clean those . Having a battery terminal tool (cheap, auto parts store) and a standard wire brush.
If you've done all that, the starter solenoid (which may be integral to the starter) is the next suspect.
The starter is the last step in the chain. If you need to replace it, I have had good luck with 'refurbished' starters and alternators, just make sure they are warranted.

First check your battery, if it is OK, then it can be corroded terminals at the battery itself or where the heavy cables terminate; at the starter input terminal (+ cable) and where the negative is attached to either the block or chassis. Both ends of these cables should be cleaned now and then and either dielectric grease or even petroleum jelly can provide some protection against renewed corrosion. NOTE: ALWAYS disconnect the negative battery terminal first! If a tool slips and ends up between the + terminal and any grounded point, it may melt the tool. If the negative is first to be disconnected, it doesn't matter if you slip on this one.

The problem doesn't need to be the starter; the first thing you should eliminate is the chance that the problem is only poor contact at the battery terminals, the point where the negative cable is attached (either body sheet metal or engine block) and the starter terminal itself.
You can buy a tool for cleaning battery terminals at any auto parts store or, if the battery has side terminals, use any wire brush. - Disconnect the negative terminal from the battery first. - Then remove the positive terminal. - Clean all parts throughly. - Reattach them. - Try starting the engine.
If it doesn't start; - Disconnect the negative terminal again. - From under the car, locate the starter; it will be at the junction of the engine and transmission and it will have one end obviously butted against the transmission housing. - Remove the heavy cable from the starter and clean the cable end and the starter terminal. - Reattach the cable to the starter. - Reattach the negative battery terminal. - Try starting the engine.
If it still doesn't start, it may still be only a drained battery so find someone to 'jump' your battery and try to start the engine again. If it still doesn't start, then the starter could be bad.
I've had pretty good luck with rebuilt starters and these will cost far less than new.

This is almost certainly a bad starter/solenoid sticking. If you hear the click sound hit the solenoid(NOT the electrical connection!!) on the starter several times with a hammer. If it starts you definitely need a starter. This trick will only work for a few days - so replace that starter.(disconnect battery before replacing it !)