I just installed a JVC KW-AV790 and grounded the parking brake lead to the chassis and everything works. Video plays while driving. I did install a video bypass switch, but was curious what would happen if I disconnected the switch and just grounded the lead. To my surprise, everything functions properly.
My concern is am I causing a problem internally. I Don't believe I am, but it doesn't hurt to ask either. I did a search on this subject and found nothing. Any input would be greatly appreciated.

Happy New Year everybody.

 

Nah, you're doing no harm to your headunit. They are tested to be on all the time (in the event someone installed it "properly" and uses it with their car/truck parked in the garage all the time). I had an old Jensen I did that with, grounded out the parking wire, and it worked great for two years until I traded in my Tacoma for my F150.

 

You'll be alright, that's how I've done 2 different JVCs