How do you determine between alternator and battery? 2003 jeep liberty frequently won"t start - no radio either, but the lights and windshield wipers do. starts right up when i get it jumped...even after only a second of charging

Sounds like you need to have your alternator checked.

Check you alternator output . Low voltage will cause shifting problems

have a load test done on the original battery as it appears that you have a shorted cell that is draining all the power from the jump battery.

have the fault codes read as that will indicate the problem area

battery dead.

THEFT system is armed; check the disarm procedure in your Owners Manual.

If this isnt solve it, could be that you need to re-synch your antitheft security module.

Hope this helps. Your feedback is important and I'll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using Fixya, and have a nice day.

Sounds like a ground problem allowing a back feed issue.

Make sure your battery is grounded to the engine and frame.

the alternator brushes /commutator worn out ,most likely the later renew the alternator with a genuine bosch replacement unti

check the alternator out put on the battery once car is running and the battery voltage also
good batt 12.4v bad bat anything below 11.9v
with engine running
should read 13.8-14.8v bad is anything below 13.0v
check these and let me know and ill help more if needs be.
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SOUND LIKE DEAD BATTERY.CHECK BATTERY CABLE FOR TIGHTNESS AND FREE FROM CORROSSION AT BATTERY POST AND BATTERY CABLES.MAKE SURE BATTERY VOLTAGE IS 12.5 VOLTS.IF NOT BATTERY NEED CHARGING AND TESTED.IF BATTERY GOOD.SOUND LIKE ALTERNATOR BAD.BEFORE REPLACING OR DISCONNECTING BATTERY CABLES OR BATTERY AND ALTERNATOR.TURN OFF RADIO SO YOU WONT LOSE PLAYING CODE.