2001 gmc 2500 hd starting issue

Kiera C. · June 28, 2020

2001 gmc HD 6.6 Have had no issues prior to this, I have 173 000 on this truck. 92 degree day.
Drove to dump today, turned off, emptied trash, finished and started it back up then drove to the gas station. Turned it off for about 15 minutes, came back out of store, turned it on, started back up then immediately died. Tried to turn it on again and it did not turn over. My dash came on, my gauges worked and it shifted into neutral no issue. Just wouldnt turn over, wouldnt even click. My only light that did not come on on the dash was my WAIT TO START icon for the glow bulbs. Had to have it towed home. Let it sit about 40 min, my husband went out to try it but used the spare key and started up no issue. Twice. No delay in turn over. I went and tried with both 3x each and it started up also, but took longer to actually start.
Last oil and fuel filter change less than 1000 miles ago. Batteries 6.months old. I havent started looking at relays or fuses.

What would be the difference between symptoms and trouble shooting a bad ignition switch versus a bad starter?
Any help appreciated.

Edited June 28, 2020 by Kiera C.