Mirror Heat - stay on?

I went ahead and did some light reading.

The relevant paragraph considering exactly your 30 minute heated mirror complaint is shown in this PDF of the actual Manual for your vehicle. (Or generally your make of vehicle over a range of some years) Your vehicle is behaving perfectly turning off the heating element after 30 minutes.

Now what I am posting after this sentence is a direct quote from one of two paragraphs in the manual regarding your 30 minute time limit and how to go about getting it changed. The link that follows is the actual Manual that this information came from followed by a chapter, verse and page you need to visit within this manual for further information.

Now I have always said I learn something new every day and this manual has provided me with a update on what a big truck does these days in pretty good detail compared to say a 2001 Century or a newer 2002 T2000 KW Tractor from back in my day. Without further ado...

Begin quote

In order for the heated mirrors to operate, the key
must be turned to ON. The heated mirror will remain
on for 30 minutes, as a default setting. The settings
can be changed by an authorized Freightliner service
technician. After the defined length of time the
heated mirrors will disengage only if the outside air
temperature is greater than 60°F (16°C) as a default
setting. Outside air temperature is monitored by a
sensor

End quote

Source Link (*You will need Adobe PDF Reader (Free download)

http://www.transchicago.com/assets/1/6/Cascadia_Drivers_Manual.pdf

My job for this morning is finished. You had a specific question, and it's answered by this manual linked to this thread.

 

My 2016 shuts off after 30 mins, but if the wipers are going, it will stay on. Also if it’s really cold out it will stay on.

 

<Going into shock>