Tried to start 2006 jeep wrangler engaged key and it sounded like when the engine is already running. Did it 2 times then started on 3rd try

SOURCE: 1995 jeep wrangler starting problems

would replace starter and inspect battery, cables/terminals also if problem still chattering u may have damaged the fly wheel the chattering is the starter not fully engaging the fly wheel. most likely starter but bad battery cables would also cause same symptoms hope this helps u

SOURCE: 2006 jeep wrangler check engine light came on it

There is a software update for the PCM that addresses this issue. TSB 18-028-06

SOURCE: MY 2006 JEEP GRAND CHEROKEE WOMT START SOMETIMES.I

where is click comming from..clean battery terminals and also check all wires to starter to make sure not loose when in fail mode have someone hold key in crank mode and take hammer and tap hard on starter if it starts replace starter.. if not get back with me

SOURCE: 2006 Jeep Wrangler won't start

First, make sure you can turn the engine by hand. If you can't then the starter can't turn it either. Have someone else turn the key and look for the source of the click...may be a relay. Go over the starting circuit with a volt meter. Check for power at the starter main terminal and then with the key turned to "start" check for power at the trigger terminal on the starter. Check battery voltage and check relay operation.
You have a neutral safety switch on the transmission if its an automatic and a clutch switch if it's a stick. Check them as well. Make sure battery grounding on fender and block are also clean and secure.

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SOURCE: 1995 Jeep Wrangler 2.5L Fuel Pump/Check engine light

Could be one of several items...I'd check the fuel pump relay, auto shutdown relay and the ignition switch itself. I'd bet on it being one of those relays but, we all have been fooled at least once!!! I'd also make sure that body and engine grounding is good and clean. Relays can't work properly without a good ground.