You can search about orange rainex harming the tank sensors and the dash ligh comes on for newer cars that have that type of sensor. The silicone that is so helpful to help the window bead up water also coats the sensor contacts in the tanks. I had to help
@tlucier clean his tank after perennially using the Rainex. Here is just one article, there are many. Great product but buggers up things a bit. More of a nuisance really than a problem. Older car, not an issue.
PSA: Do not use Rain-X Windshield Washer Fluid (the orange stuff). It leaves a coating in the washer system that destroys electronic fluid sensors...
www.ferrarichat.com