How to change 12v outlet from always on to turn on and off with ignition

I have a 94 gmc sonoma sle 4.3L V6 and I wanted to make the outlets turn on and off with the ignition but I don't know how to do it exactly. I have 3 outlets which are always hot (have power), and I would like to be able to at least make them all turn on and off with the ignition. But it would be nice if I could choose which individual outlets I want to have on all the time and which ones I want to turn on and off with the ignition, this would be done with either a switch of some sort or have the ability to move the respective fuse over as if it were a jumper.

gmoon2 years ago

Isolate the outlet circuit and add a relay for each outlet, controlled by circuits that are "hot" when ignition is on.

You could set this up with a three-way switch, ON would bypass the relays (normal always ON operation), OFF would cut power completely (open circuit), AUTO would use the relays to close the circuit when the ignition is on.

SLIMDADDYC (author)  gmoon2 years ago

thanks gmoon. That makes a lot of sense now.

Sure. One other note, if you do this -- make sure the relay coils aren't energized when the ignition is off. Otherwise it's additional current drain on the battery when the vehicle not being used.