Technical 2007 X250 NO START, Does temperature matter?

[marupuyo]

Hi,
My car is fiat ducato x250 2007 year model.
Please tell us about ducato's ENGINE STARTING EQUIPMENT.
Even with the ducato key ignition in the start position, the starter motor sometimes does not respond.
However, even if there is no reaction in the morning, the starter motor will react and the engine will start around noon as if nothing had happened.
From this, I suspect the electrical system, but I can't find any relays in the ENGINE STARTING EQUIPMENT.
So far I have replaced the starter motor, ignition switch, earth strap and battery.
Are there any relays or switches used anywhere other than the KEY SWITCH or the starter motor?

Regards,

 

[Communicator]

Does the vehicle have an automatic gearbox? If yes then the gear selector must be in "P" position to allow use of the starter motor. In x244 models, this interlock was achieved by using a relay with contacts in the starter solenoid circuit.
I do not see why a relay should be affected by normal ambient temperature changes.