What activates the heated side mirrors on 2011 Equus Ultimate?

[RCaauwe]

I can't find any information about what activates the heated side mirrors. There is a little symbol (icon?) printed on the mirror, so I assume it should be able to be activated in some way. Is it a temperature sensor? Does it come on when the windshield defrost is activated? (I tried that today with an outside temp of 32 degrees while it was snow covered). The mirror didn't even feel warm after driving 20 minutes or so.

 

[rve]

If your vehicle is equipped with the outside rear view mirror defrosters, they will operate at the same time you turn on the rear window defroster.

http://www.heqmanual.com/rear_window_defroster-161.html

 

[Tj222]

If your vehicle is equipped with the outside rear view mirror defrosters, they will operate at the same time you turn on the rear window defroster.

http://www.heqmanual.com/rear_window_defroster-161.html

rear defrost button works with the light indicating on/off but no air towards rear defrost and at the same time the exterior mirrors stopped heating so I think it’s a fuse??

 

[Roys1337]

rear defrost button works with the light indicating on/off but no air towards rear defrost and at the same time the exterior mirrors stopped heating so I think it’s a fuse??

Rear defrost doesnt work with air, theres no vents blowing onto the back window that I am aware of. It uses the grid lines on the window to heat it. A good way to test is to turn it on, let it sit for 5 to 10 minuts, then press your hand to the window and see if its any kind of warm. If you have a digital thermometer or infared camera that can see the heat from them, that would be better.

If theres no heat to the window grid, and no heat to the mirrors, then I would definitely check the fuses.