I have had issues periodically with starting my 05 Grand Cherokee Limited.
I thought the battery(brad new optima yellow top) was dead and boosted but no go as I would get lights etc all worked but I could here a click : like a selenoid. If I turned the key back and forth many times it would finally start.
Took it to the mechanic and he tried it 10 times and it always started without a glitch. Two weeks later same darn thing and I had to turn the key back and forth 50 times ,. Each time i could here the click up in the engine until it finally started.....could it be the starter relay??