Where can I find a switched 12 volt source?

I want to power my radar detector with a switched power source so that it turns off when the power switch is turned off. I found a couple of constant on power sources in the box in the engine compartment and I intend to use #4, a 10 amp fuse, which is listed as "no circuit" and is on all the time for my cellphone, which I want to charge even when the ignition is off. #14 also seems available. But I can't find any unused circuits that switch on and off with the ignition.

Any suggestions?

 

Yeah, I was trying to avoid having to get to the back of the power outlet. I wanted to bring a wire in from the fuse box so I could just conceal it under the trim until I brought it to the side pillar and up under the front of the headliner or actually wedged in between the windshield and the headliner trim.

I will do that if I can't find another source that is switched, but then why don't I just find the fuse that feeds the outlets? Duh. Let me try that.

 

Thank you! I remember that picture now. There are just so many informative posts that I can't keep track of all of them. I appreciate your help. I will be going in there this weekend. Thanks again.

 

Is that fuse in the engine compartment fuse box or under the dash?

 

Thanks. I hate manuals, but I would have checked it eventually. It was in my trunk and I had already packed for a trip so I can't get to it until I unload my bags tonight.

Thanks a lot.

 

Thanks, I have been on the road a lot the last few weeks so I haven't had enough time at home without heavy rain to work on this, but I think this weekend I will take this on. Very helpful answers. I will check them out.