The standard file is "Timecyc.dat", but with darker and more realistic static shadows.
I recommend installing the ASI plugin "No Shadows":
• RUS: gamemodding.com/ru/gta-san-andreas/cleo-scripts/55349-sa-no-shadows.html
• ENG: gamemodding.com/en/gta-san-andreas/cleo-scripts/55349-sa-no-shadows.html
To fix the lighting in the game, install the ASI plugin "SilentPatch v1.1 Build 32":
• RUS: gamemodding.com/ru/gta-san-andreas/others/90690-silentpatch-v11-build-32.html
• ENG: gamemodding.com/en/gta-san-andreas/others/90690-silentpatch-v11-build-32.html
The mod requires:
• "Mod Loader";
• "ModdedSAA".