2012 T800 nav system

It will be helpful to understand the type, model number and brand of this item?

If you can get behind the panel that contains the Nav, maybe you can disconnect the cables feeding power to it?

What kind of alarms are you getting? And what is this Overriding the stereo thing? Are the two the same?

By chance are you in a area where Federal Testing is underway perhaps?

I apologize for questions answering your question. I wish to learn more and at the same time not come off as stupid talking about something I know nothing about? A few more details will help me formulate a good response.

I know what Nav systems are for and have ideas myself. However, persoanlly I do not rely on Nav systems because none of them have proven to me that they contain information such as that might be provided by a good motor carrier's atlas in terms for bridge weights and low clearance restrictions.