What are the common issues when the rearview mirror heating fails?
3 Answers
Generally, the failure of rearview mirror heating is caused by either a damaged mirror or a blown fuse. The function of rearview mirror heating: The rearview mirror heating function allows the car to remove rainwater or fog from the mirror surface by heating during harsh weather conditions such as rain, snow, or fog, ensuring clear visibility on the mirror surface. The principle of rearview mirror heating: It involves installing an electric heating pad or heating film inside the mirrors on both sides. There is usually a rearview mirror heating button on the car's center console. Once the button is pressed, the mirrors heat up quickly, and the effect can be seen soon. The temperature typically ranges between 30 to 60 degrees Celsius.
When it comes to a broken rearview mirror heater, as a car owner with over 20 years of driving experience, I've encountered this issue several times. I remember one winter when the mirror fogged up completely, making it impossible to see behind me. After checking, I found the fuse had blown—just popped open the hood and replaced it myself, easy fix. But later it failed again, and this time I discovered the heating element had aged; the internal heating wire inside the mirror had burned out due to unnoticed accumulated damage from minor impacts over time. Poor wiring connections are also common, especially in rain or snow—corroded connectors interrupt the current, leaving the mirror cold. My advice: first check the fuse box location (usually under the steering wheel in most cars) and try swapping the fuse in minutes. Also, parking in shade to avoid direct sunlight can extend the heater’s lifespan. Don’t delay repairs—fix it promptly to avoid driving hazards. Though a small feature, rearview mirror heating can be lifesaving in cold or wet weather by ensuring clear visibility.
As a car enthusiast, I always enjoy tinkering with my car. Common causes of rearview mirror heating issues include blown fuses (usually due to excessive current causing instant melting), damaged heating elements (the metal wires can break after prolonged use), malfunctioning circuit control switches (worn contacts preventing power flow), or broken/aged wiring (insulation cracking after long exposure to wind and rain). For troubleshooting, use a multimeter to measure current and repair areas with no signal; test the switch (located on the door or center console button) by repeatedly toggling it to check for jamming. Start with checking fuses—simple and cost-effective, with most manuals indicating their location. If that doesn’t work, take it to a shop for a full circuit safety inspection. Don’t underestimate this issue: without heating in heavy fog, mirrors can fog up and cause accidents. Regular circuit maintenance is the best policy.
