Auto Wipers and Tint

[TexMarQue]

So I pulled the trigger and got ceramic tint installed on all the windows, including the windshield. Today was the first time it has rained since the tint was installed and my auto wipers aren't working properly. I'm guessing that this means the sensor for the wipers is hidden behind the giant plastic dome the rear view mirror is attached to, and the installer must have tinted over the spot where the sensor "sees" the rain. Can anyone provide insight into how the wipers actually detect the rain? I recall hearing someplace that the windshield detects the pressure of drops of water, but I'm calling that bogus based on variable wind pressure when driving that would cause havoc with that sort of sensor. I'd like to know if removing the tint behind the mirror will fix the issue or not before I try to get it taken care of. Thanks!

 

[Riveyman]

Interesting question.
Found this: optical sensors are used to detect the moisture. The sensor is mounted in contact with the inside of the windshield, near the rearview mirror. The sensor projects infrared light into the windshield at a 45-degree angle. If the glass is dry, most of this light is reflected back into the sensor by the front of the windshield. If water droplets are on the glass, they reflect the light in different directions -- the wetter the glass, the less light makes it back into the sensor.
The electronics and software in the sensor turn on the wipers when the amount of light reflected onto the sensor decreases to a preset level. The software sets the speed of the wipers based on how fast the moisture builds up between wipes. It can operate the wipers at any speed. The system adjusts the speed as often as necessary to match with the rate of moisture accumulation.

So looks like the tint needs to be removed from the sensor area


Link to article

 

[TexMarQue]

So looks like the tint needs to be removed from the sensor area

A great answer with sources cited. Thank you, Riveyman.

I've also been looking on one of the 1500 forums, and see mixed results with tinting over there, too. Going to try cutting a circle around the area where the sensor is. No idea when it will rain again, but I'll try to remember to report back.

 

[TexMarQue]

Update...Went back to the installer thinking I was going to need to have the tint cut around the mirror. Didn't want to try to freehand cut a circle myself because I can't draw a circle to save my life. Took the mirror off and found that the sensor wasn't seated properly. We also discovered that the sensor isn't installed flat against the glass as we had both expected. There is some sort of film installed in the area where the sensor snaps in with a thin layer of fluid or gel in it. When the sensor is seated correctly, it isn't visible at all from the outside of the windshield. When it isn't seated properly it has the appearance of a gob of silicone smeared across the windshield. Seems to be working like a charm now that it is seated properly against the little gel pocket.

 

[Great White North Eh]

Update...Went back to the installer thinking I was going to need to have the tint cut around the mirror. Didn't want to try to freehand cut a circle myself because I can't draw a circle to save my life. Took the mirror off and found that the sensor wasn't seated properly. We also discovered that the sensor isn't installed flat against the glass as we had both expected. There is some sort of film installed in the area where the sensor snaps in with a thin layer of fluid or gel in it. When the sensor is seated correctly, it isn't visible at all from the outside of the windshield. When it isn't seated properly it has the appearance of a gob of silicone smeared across the windshield. Seems to be working like a charm now that it is seated properly against the little gel pocket.

Good info

 

[cdugas4]

It's likely your installer hit the sensor during install. I'm thinking of tackling adding the auto wipers per the thread in the 1500's forum which requires replacing that sensor. In normal trucks it's only a sensor for humidity for the auto HVAC but in there is a nearly identical sensor which contains the auto wiper sensor too.