Strange starting issue w123 300TD
 

So I'm puzzled about an issue with my 82 300TD. It starts fine when the engine is cool I.e. every morning. But occasionally after the engine is hot, it has trouble starting again. Turning the ignition key produces an audible click from the starter, but the starter doesn't attempt to turn the engine over. I've replaced the neutral safety switch and the starter. I am guessing it might be poor wiring connections, since it only occurs when the engine bay is hot. After letting the car sit for a while and cool down below 80C, it will fire right up.