Starting problem in hot weather

On my Passat Variant 90PS-TDI, manufactured in 1995, I've been experiencing the following starting problem for a few days now, particularly in hot weather after a long period of inactivity:
1. Attempt: Silence, but all control lights are normal.
2. Attempt: sometimes like 1. 'Usually, it starts up perfectly fine.'
3. So far, my attempts have always been successful.
He has never malfunctioned during driving, and there have been no issues so far even at normal temperatures. I suspect a relay that may not be actuating, but I'm not sure which one is responsible for this.

Thank you for the advice.
wolfman

Hello, what exactly did you mean by "silence" on the first attempt?

You turn the ignition key to the right until it's fully engaged, but nothing happens?
If you don't hear a "click" coming from the engine compartment, you should check the ignition switch and wiring to the starter (thin red cable).
Does it "click" but nothing else happens? Check the starter solenoid, check the thick cable to the starter, and see if the starter gear on the shaft is moving. If not, try lubricating with copper paste.

Hello, Rainer

Hi

. . . should be used very consciously in the area of electrical contacts:

I once checked the rear window lock on a friend's car, which was constantly burning out every time it was switched on.
Nothing found until I disassembled the switch: inside, a lot of copper paste, and by following the traces of the paste, it was clear that the contact for the load was connected to the ground contact of the switch's lighting via a blob of paste --> short circuit as soon as the rear window was turned on.

By the way: Copper paste can always be used, not just for mounting *gg* Scherzle made. . .

Did the starter ring on the shaft need some lubrication with copper assembly paste?
Unfortunately, my old Passat sometimes got stuck because it lacked lubrication and had some rust. Effect:
When turning the key, you only hear a "click", but the ratchet didn't move far enough on the shaft to engage in the gear with the flywheel (which was also in a very bad condition).

Hello, Rainer