"Floating ground" in dash or headliner area of 2016+ models

Hey all:

Mostly lurk on here but here is a question for the electrical experts. Doesn't anyone know of a "floating ground" wire in the dash or headliner (electric controls near rear view mirror) areas of the 2016+ models? My nomenclature is probably wrong, but I am looking for a ground that is acts as a 12V positive when the car is running but becomes a ground when the ignition is turned off.

On my 2005 I was able to tap into a red wire off the head unit that functioned this way.

Thanks!

 

Trying to understand what you are searching for, l know of no ground wires that switch over to being a power wire. If you are needing a Ground then any bare metal on the body should be sufficient. Maybe you are seeking an Accessory Power Wire which will only supply power when the ignition is on, a simple volt meter should help you locate one if that is the case.

 

What you are looking for is a power wire that grounds out
floating ground is something different, the output of the AC Inverter is a floating ground do to it not being tied to an earth ground

Sounds like you want a power wire that is controlled by a DPST relay that has the NC terminal grounded to the body so the power lead connected to the device connect to ground when power is removed from the relay

Any the $64k question: what for

 

Thanks for the help. It's for a flashing LED for the dash. In my 2005 I used positaps to connect + lead of LED to a yellow wire off the radio head unit and the - lead to a red wire off the head unit. When I shut off the ignition the LED would start flashing, perfect setup. I can't recall where I got the information to locate those particular wires on the 2005.

Would like to know if there are equivalent wires on the 2017 with factory head unit.

 

Done! Easy day...pulled radio and tapped (used posi-taps red for light gauge wire) into R30-3 (grey) and R30-4. LED now turns on when I kill the engine.

 

Glad to hear you got it figured out.

 

Thanks!