Rep Power: 0

I've had this problem before but it fixed itself before I could get a diagnosis.
I turn key to accessories and the dash lights come on along with the radio but once I try to crank the engine I get one click and all the lights turn off. I was able to get it to AutoZone a few days ago and got a good battery, good starter, bad alternator result on a test but I'm not getting any other bad alternator symptoms. I've checked battery connections and it shows a 12.4v on a multimeter. I haven't done anything to the starter and alternator yet.

Anything in specific I should keep an eye out for when checking anything else out?

 
Rep Power: 222

Might be a bad ignition switch