2000 JGC have to wingle key to crank motor.

A bad starter motor maybe drawing to much current. Have it checked.

There is a fuse or fuseable link between the alt and battery, and the alt gets a signal from the key to activate the voltage regulator.
I would check for batt voltage at the alternator and you may need a wiring diagram to check for key voltage.

check ignition module, you may have fried it, if motor turns over the solenoid is o.k. -- your probably not getting any fire to the plugs, check to see if you are getting any spark at plugs

one easy way is to have someone hold key in crank ing position,then another person needs to hit or tap the starer housing itself.if engine begins to crank intermittently or ur cliking noise turns into small jolts of the starter trying to crank then u can bet its the strtr motor. u do need a charged batt for this test. also chek ur battery grounds they can dramatically affect starter operation if we have a voltage drop anywhere in starter circuit .chek batt cables r tight on batt posts, loose batt cables on battery will also give u clicking noise w no starter operation

Ok, if the cranking amps is like 70AMPs or 100 AMPS as measured by an inductive ammeter on the battery cable when starting, and it does NOT start, then it's a bad starter.

However, if it does start, that's normal.

On a car that old, I would check that the battery cable ends are squeaky clean, wire brushed, or even replaced if cleaning is not possible.

Usually, a battery that is tested good will be good under a load test.

Also, try to use an ammeter to find out if there is a drain on the battery above .2 A while it sits there turned off. This could lead to a solution if you investigate where a short may be.

Obtain a 12 volt test light, ground the clip on the negative battery post, and check for light at the large terminal on the starter solenoid. If lit, have someone try the key--if the light goes out, place the light on the battery positive post and try the starter again. If it goes out again, either the battery needs to be charged, or it is defective. If the light stays lit in the first test, then place the light on the starter motor terminal and retry the key (do you hear a fairly loud click?). If nothing but the click, replace the solenoid itself. If no click at all, test the small terminal on the solenoid and try the key. If you get light, replace the solenoid. If no light, check for blown fuses. If ok, then suspect a bad ignition switch. Hope some of this helps!

check your voltage regulater sometimes these are internal and if thats the case replace your alternator

You need to change that solinoid.Just remove the starter motor and have a new one fitted.

hello,try to look your stater motor,big cable connected to battery,you can install your cable to have power, only for opening your trunk,charge your bsattery outside,ty

First thing I would check is to see if you have power at the trigger wire of the starter motor while someone is trying to start the vehicle for you. It will be a Yellow with a light blue trace. If you do then I would check to see if the main battery cable has power to it all the time when someone is trying to crank it. If it does then I would hold a test light on the case of the starter motor and have someone try to crank it. Make sure that the ground you use for this test is on the negative battery terminal not just anywhere on the car. If the test light lights while you are cranking it then you have a bad ground. Hook up a set of jumper cables from the battery negative terminal and clamp it directly on to your starter motor and see if it starts. If you check it and the test light doesn't light up and all the other checks are good then your starter motor has failed. If one of the other tests has failed then you have a starter relay problem or something else. let me know what you find out.