Ok thanks that answers a lot of questions. So the mirror heaters could have been active for a long time maybe, how would you know in florida things are warm there all the time. You should be able to pull the relay for the mirror heaters and stop the voltage drain. Don't need mirror defrosters in flordia do you? You should have a defroster switch on your HVAC panel that controls the defrosters, I wonder if that's working correctly? The #5 fuse in the fuse panel, controls Heated Mirrors, Heater and A/C Control Head, Heater and A/C Programmer, can't remove that fuse. The radio and mirrors on the same circuit is puzzling.I will try to track down the exact location of the relay mirror location..

 

Thanks @thomas77 ,

Appreciate all the feedback!

The mirrors AFAIK also work to defog, which we do get quite a bit of in FL. In my area, it does get quite cold for about a month - I'm in the Panhandle - NW Florida and we get about 30 days of 40 degree weather as well as a few days of frost and freeze

Last year my well pump froze and split open and had to be replaced - so it does get fairly cold here once in awhile

In addition mornings we do get quite a bit of condensation on windows of cars - specially the windshield and rear window.

My other vehicles that don't have mirror warmers I just use my finger to wipe the condensation

 

Back to the original question, what's making the heaters stay on? Bad dash switch, stuck relay, internal short somewhere? Some car Heaters have timers, I'm not sure if you have that, your cars option codes might help on which option you have. If all else fails you can wire in a separate switch for the heaters..

 

IIRC, the heated mirrors on my Tahoes were controlled by the defroster in the HVAC head unit. There might be a switch problem in that unit.

 

Got the car back today.
According to the mechanic, it wasn't a relay
They disconnected the mirrors from inside the door and the radio works and there is no more draw on the battery

I don't know, IMO electrical stuff is so difficult to isolate and I have to trust and be at the mercy of the mechanic.

At least he didn't charge me anything for disconnecting the mirrors.

 

Sounds like the problem is in one/both of the mirrors or wiring.

 

Sounds like the problem is in whatever controls the mirror heating circuit.