Windshield sensors not working

There are aftermarket windshields that have rain windshield sensor, but you need to make sure whoever installed it included it and put it together properly. Here is some basic info regarding the tech.
Rain Sensor & does my car have one - CPR Auto Glass Repair
I don’t think all Prius 4th gen have that feature? So you may find windshields without it? Which that is what I would guess with your windshield if it does have it, then the sensors need to be connected to the vehicle.

 

I'm also having a problem with the HUD being blurry following a windshield replacement. This is an aftermarket windshield. I did not have a problem with a prior replacement when I used a Toyota windshield, but the price has escalated to $1400, so aftermarket it is. What did you do to fix your blurriness problem?

 

Toyota works the thickness of the windshield right there so the two glass surfaces are not perfectly parallel, and the two reflections of the HUD meet at your eyes and look like one. A windshield made of plain flat glass will give you a double image.

 

I just went through two replacement windshields, both with Toyota badging and designed for the HUD and auto wipers. The auto-sensing wipers didn't work with the first replacement, which I brought to the attention of the installers. But then 11 days later I was needing another windshield replacement. At the shop I mentioned again the problem with the wipers and they did it right the second time. The sensor on the inside of the glass was the same, but the sensed area on the windshield looked different in the second install, and I'll admit I am at a loss to explain how that sensor works or doesn't work. I heard that the area on the windshield where the HUD shines has some sort of optical polarization treatment which makes it work.