hello,

you are on the right track as far as getting your cars components properly tested. But i had a couple questions.

1 does your car click whenever you turn your key?

2 you said this was random, so is there a grey area where the car tries to start but doesnt, or does it work perfectly when it works and doesnt when it doesnt work?



KEy points to your situation
#1: (the answer to question number two above goes here) if you car simply works or doesnt work, it REDUCES the chance(there still is a chance) that the problem is in your charging system. If it was then your starting would be sluggish before or after the problem arises. or you wouldnt have enough voltage to turn the starter and the solenoid would just click(if this was the case then you would have to charge your battery or jumpstart it before it would run again, and that doesnt sound like your problem)
#2: the randomness.... . If it comes and goes it is probably a bad switch or connection, or possibly a bad-spot on the starter.
#3 if your charging system checks out and your car still clicks(if it ever did), it will probably be a bad connection between your solenoid and starter or a bad spot on the starter itself. But could still be in the ignition(not very probable.)