Front Camera in Rear View Mirror

Hello!

I would like to install a front camera that connects to my rear view mirror and that can be turned on or off with a switch. My 2012 Tacoma currently has a rear camera connected to the navigation system but it does not use the rear view mirror screen (except to show the temperature).

I have searched for this topic across the forum but have yet to find anyone who has attempted it (just individuals who have hooked a front camera up to the navigation and use a toggle switch between the front and rear). Does anyone have any ideas on how to accomplish this or links to threads that I missed on the subject?

Thanks for your help!

John