What RPO do you have in regard to the mirrors? I have the standard DL8- power/heated. They have a switch for moving the mirror, but not to heat. They are automatically heated.

 

I'm not sure what you mean by RPO? The truck has power mirrors and a switch to move them, but there is no heated mirror switch nor heated mirror symbol on the mirrors.

 

Yeah I don't have a switch for heat or symbol either, but they are auto heated. Yours may not be? Look in your glove box for the RPO sticker that has codes for the trucks options and see what you have for sure.
GM Master RPO Code Listing

 

in my 02 Sierra, the heated mirrors are on the same circuit as the rear window defroster, so when you hit the switch by the HVAC controls for the rear defroster, the mirrors also heat up.

 

^ Same as my 01 Sierra.

If you replace your A/C / Heater controls with one that has the defroster switch, then you may be able to control the heat for mirrors, BUT I don't know if they all have the wiring and/or BCM programmed for that functionality or not.

 

Well, I don't think that my truck has a rear window defroster. I'm going through the RPO codes in the glovebox, found code D48 which shows electric mirrors, but not heated. I also don't have a rear defrost switch on my panel. I have the regular front windshield defrost on my airflow setting dial, don't know if the rear defrost turns on with that or just isn't there? I've attached a photo of the sticker if someone knows a bit more. I appreciate everyone's input.

Thanks.

 

if you don't have the little button that activates Rear-window defrost, you won't have it. I've never seen a vehicle that has rear-window defrost on with the regular HVAC controls. Every vehicle I've ever owned over the last 30+ years has had the separate button for it. I'm guessing that the setup for heated mirrors is also probably not there. I'm new to Chevy/ GMC's so I could be wrong, but that'd be my guess.

 

So, say i wanted to install the wiring for the heated mirror myself then. Do heated mirrors have any kind of ambient heat sensor so they know when to turn off, or do you need to wire a switch to them? So, can I just tap into a wire that's on whenever the car is on and always have power going to the heated mirrors, or will that just always heat the mirrors and burn out the heating element? I'm guessing some kind of switch is necessary.

 

sorry, can't help you with that... I'm still learning my way around the Chevy/ GMC world after exclusively driving real man's trucks (Dodge's) for the last 30 years, and this is the first truck I've ever had with power/ heated mirrors. Have had other trucks with rear defrost window, but none with heated mirrors before this one.