Strange issue with a 2001 Grand Prix (3.8L vin K)
No crank when the car sits in the hot sun for a few hours, has nothing to do with a engine hot soak. All dash light seem to pilot, just no crank.
If you let it cool off after the sun goes down a bit it will crank and start. All you have to do is park it in the hot sun (Texas 95 degrees F), even if the engine bay is cool after a few hours it will not crank.
Starter has been replaced.
As far as my research shows the ign switch is fed form the main panel (40a fuse) under the hood (near battery) directly to the ignition switch, then goes through the neutral safety switch to the starter, no theft deterrent intervention. I have tried moving the shifter up and down the range with key in start position with no luck, so I assume neutral switch is good.
Schematic pulled from AllData, appears to be the way GM has done it for ages, if anyone has better data on the wiring please post or link to it.
I cannot do any diagnosis until Tuesday, check voltage in and out of ign switch, same for neutral safety switch, check voltage at starter solenoid with key in start position. Check Starter install and wiring.
Has anyone seen this specific behavior on this model or similar before?
I will post back on Tuesday if I learn more.