Modern vehicles have many new and also some legacy sensors that you should be aware of when cleaning the inside of your vehicle. Particularly when you clean the inside of the windshield glass or the dashboard. The cleaning and conditioning chemicals can leave a residue or possibly damage the sensors' optical films.
New cars have systems like head-up displays, automatic headlights, automatic windshield wipers, and forward collision prevention and lane-keeping sensors that can all be hit with the spray from your cleaning bottle. Most manufactures specifically prohibit you from cleaning the lens of the sensors. Subaru, for example, says about its EyeSight camera system, "Never touch the stereo camera lenses, and do not attempt to wipe or clean the lenses. Doing so could damage or soil the lens, and lead to improper system performance. If you ever touch a lens for any reason, be sure to contact a SUBARU dealer."
When you spray any sort of glass cleaner or dash conditioner, it doesn't just hit the spots you aim at. Particularly when you spray the top portion of the windshield. Overspray drops fly well beyond the target and they can fall down onto the head-up display aperture. They can also spray into the and onto the EyeSight lenses in Subarus and the similar systems other automakers offer.
Dashboard conditioning and cleaning solutions are worse. They are a milky cloudy liquid, and when they are left to dry form circles of precipitated chemicals. We suggest not using them at all, and instead, using a cloth dampened with water. In other words, spray the cloth, not the dash. The top of page image and the vehicle shown in our video is a Mazda CX-5. This vehicle has a color head-up display, called an "active driving display" by Mazda. In the manual, Mazda warns about using the wrong cleaning methods and suggests using compressed air, like that one might clean a keyboard with.
Glass cleaners can contain ammonia, vinegar, and surfactants. All of which can harm thin films applied to optics intended to act as anti-glare agents. The next time you reach for a spray bottle to clean the inside of your car, be aware that some of the most sensitive and expensive parts of the car can be put at risk.
Older systems such as the heating element wires on your windshield and rear hatch glass can also be damaged by improper cleaning. Avoid them, or wipe gently along the lines, rather than across them. If you have any stories about cleaning gone wrong, please tell us in the comments below so we can all learn better methods.