Jeep has power but won"t start

Faulty starter solenoid

First I suggest scanned the ECU in order to know what fault codes is stored there. HERE procedure.

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I would check the fuses and then for power in and out of the key switch.

Check fuses first, but could be needs new CPU

Try starting in neutral. Gear sensor may be heating up and not registering park.

Your jeep is suffering from what is called the "delayed check engine light problem". Your main computer ecu is in need of repair. Some internal components, ones that normally send power to energize the various engine relays, have gone bad from age. Have the ecu repaired. That services is offered on ebay.

note that you never once said car can be driven? why?
job1, can you do job 1?
battery is going dead
if head lamps are dim its battery going dead, (not dash HEADs?)
notice is did not say battery was bad only discharged.

if engine starts is charge.battery lamp glowing.
i engine is dead, can crank it.
get a jump, call AAATOW
or find a loaned battery that is charged.
buy a battery charger and use it.

also cars can have phantom drains, as you sleep battery goes dead. (ask)

start solenoid sounds like the culprit. the start is a breeze to replace. 2-3 bolts and the two power wires. make sure you disconnect the bat. once you have it off the auto parts store should check the starter for free. have them do that befor you buy a new one. also check the fuses if the starter and fuses are good then the ignition is the final link to this puzzle hope this helps

electronic key on 2008 jeep cherokee says key damaged or key not programmed. car won't start. some things work but radio won't come on. etc..

If you hear relays clicking sometimes and the jeep won't start, at those times, is the check engine light illuminated on the dash, or not? If no check engine light is on the dash, at times when the jeep won't start, your ecu is in need of repairs. The ecu sends power to the ignition and fuel relays and when the ecu starts to malfunction, the relays usually start clicking.