Ive done a search already and all the treads seemed really old. I put a dash cam in my truck that powers off when the truck is turned off. But all of the 12v outlets in the truck are constant power. Seriously why?? Dumbest idea ever. Is there any way to change one of them??

 

Everyone that owns a car from a japanese automaker complains that the 12V ports shut off when the car does. It would be much easier to wire in a 12V plug that is switched on and off with the ignition. Or get a japanese car.

 

Easiest would be to add a SPDT relay. Use the existing wiring to supply terminal 30 on the relay and 87 to the outlet. Hook up terminal 85 to a keyed 12v source and 86 to ground. It would only power up with the key on and it would be my first choice if I had to.

 

That would absolutely work, another less involved way (since your just powering low amp items) would be to just run another "power wire" from a switched 12v source in fuse panel & disconnect your constant power wire. You can use 1 of those "fuse taps" from the auto parts store, just make sure you place the tap on the non-power side of fuse leg, that way the fuse can still blow if needed.