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Hello my Xperia ™ z 5 premium dual proximity and notification light not functioning need some help
Hi @Dani_123, sorry to hear about the sensors not working. 
Have you tried doing the inbuilt test in the device for the sensors and what was the outcome? If you haven't done this test, you can find it in Settings > Support > Xperia Tests > Light sensor/Ear proximity.
You can also make sure that there is nothing covering the sensor on the device, or that there is any moist or dirt on the sensor. On the link below, you can see where this sensor is placed (number 4).
https://support.sonymobile.com/global-en/xperiaz5premiumdual/userguide/overview---se/
Let me know how it goes! 