DC 12v power source

Whats the best way to install a extra switched DC 12v power source for a GPS unit. Thanks for any help. 2000 Park Avenue.

I would probably go to the back of a cigarette lighter outlet that isn't considered a power supply. I believe these outlets switch with the ignition, and it is 12 volts. However, I believe the ones designated as power supply stay on when the car is off. I'm not certain on this, but I helped someone replace a radio in a 99 Cavalier that had the same digital signal instead of switched power going to the radio. I had to go to the fusebox & find a switched fuse, as the cigarette lighter was dead, but the cigarette lighter would have otherwise been easier.

Thanks for your answer. I had thought about going to the fusebox. But I wonder if taking the plastic moulding off under the steering wheel and then looking for a switched wire at this location would be another approach. Then I thought I could use a blue or red wire tapper and hook onto one of these wires. Thats how I use to do it some 10 or 15 years ago but I am unsure if this would be a good correct way to do it on newer cars.

Just wondering if anyone has ever used these products. Littelfuse Add-A-Circuit Fuseholder for Mini Fuses or Wirthco Fuse Block Add-On Circuit Tap #30003.

These are the items I used to make a SWITCHED power source. I went to the fuse box under the glovebox and found a switched fuse. I then piggybacked the add a fuse to this power source. I then plugged in my auxiliary power source and mounted it to a dash location. You can buy theses items at Auto Zone.

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