According to the manual for my 2013 Honda Fit, the button for the rear windshield defoggers also heat the side mirrors. Is there any way to confirm that the side mirror heating is actually working? I can't feel anything when I put my hand on it. Should one be able to feel the warmth of the heating on the mirrors?
The background to this situation is that my car was parked in a 3rd level sub-basement last year, and it was flooded. The remediation took so long that it was spring by the time I got my car back. Part of the remediation was to replace the electrical wires and modules. A few things got overlooked, e.g., reconnection of the trunk lights. When winter came back this year, I thought that the rear defogger wasn't working and Honda did tests to show that it did. It turned out that the defoggers just aren't that effective on the Fit, taking a long time to heat the windshield. It took a lot of effort to have Honda check it, however, and I just didn't have to energy to bug them more about checking the side mirror heating (even though I did mention my concern about it when I complained about the rear defogger). As you might imagine, I have no desire to impose on them further to check the side mirrors if there is a way for me to check them myself.
It's hard to test because I often brush off the snow before driving off, for the sake of safety. As for not brushing off the snow and keeping the car mostly stationary, the manual advises against that because it kills the battery.
It's often not snow that I'm worried about, but mist or fogging. I find that the defogger helps a bit with mist on the rear window, so I'm hoping to have that benefit on the mirrors.