Oh my Lord there are a LOT of fuses in my '17 GTS. 55 fuse positions, on BOTH sides of the dashboard. Not all of them occupied, of course, but wow.

Ok, so which ones should I consider to tap power off of for a dashcam and phone chargers?

Realizing, of course, the car has a couple of options on how accessory power is handled. Apparently some circuits stay powered "for a while" after the engine is stopped. I'm unclear on what gets powered on, and when. That and what stays powered on before cutting off.

The manual (p112) indicates the 12v sockets will remain powered even the ignition is off. But that power will be interrupted after 30 minutes.

That's a little vague. Am I take it to mean that the sockets are always live, but if something is powered on while the ignition is off then power will be cut off again in 30 minutes? I wonder, how long does the 'interruption' last? Because the dashcam has it's own capacitor/battery internally and will keep itself powered 'for a while'. I'd wonder if that conflict with/confuse the 30 minute timer?

Without this '30 minute interruption' I'd just check fuses for power with the ignition on or off. But with that feature I'm not exactly sure how to tell what stays live or not. I'm not really inclined to sit around for a half-hour between steps to see what goes off or not.

Power to the USB socket in the arm rest isn't mentioned. Curiously the manual also mentions a 'socket under the glove compartment'. Where is that?

I suppose I'd prefer leeching power from whatever gets turned on first upon unlocking or otherwise opening the vehicle. And then gets powered off within some interval of time after the key is used to turn 'off' the vehicle.

So, which fuses should I be considering?

 

I learned the hard way that the current fluctuations from the auto start stop can wreck havoc in electronics. In my old 991.1 the bottom left fuse was recommended for hard wiring.

The 12v ports turn off after 30 mins. I leave the dash cam and radar detector plugged at all times. It's a major pain to figure out which fuse to use as some turn off when you lock the car but not always immediately.

I asked at the stealership but they wouldn't give me a definitive answer, likely related to liability

 

I did some digging, and a picture of the right-hand side fuse panel is attached.

I'm using position 15. It's an accessory socket, with wire into only one side of the socket. This works fine with an add-a-tap. Power to it is switched on/off with the ignition.

There are other one-sided accessory sockets, 48 and 49. But they appear to remain powered on regardless of ignition position. Note that position 51 is empty, that's the socket I had been using. But it remained on regardless of ignition position AND stayed powered for the three days I had the dashcam plugged into it. It did not appear to get interrupted after 30 minutes.

Circled in green follow ignition. Red remains on at all times.

I have not yet determined which, if any, of the fuse positions here are handled by the 30-minute interruption.

 

I'll ask my SA again, see if I can get a more objective answer. It's time consuming see what works and when...

 

To add, fuse 15 is tied to the ignition being in the Run position (turned all the way to the right, clock-wise). It's not the same circuit as the radio lingering until the doors are opened. Or until the radio times out when you leave it running.

Which, surprisingly, I discovered the radio stays on if you had the door open when you turned the key off. I have Entry & Drive enabled, I was in the car, I opened the door, left it open and the used the Valet key to turn off the ignition (all the way to the left). The radio stayed playing. I shut the door and the radio still kept playing. It wasn't until I used the key fob to lock the alarm that the radio stopped. I don't know how long the radio would've kept playing.

My Grand Cherokee would do something similar in that it'd keep the radio running for, I think, 10-15 minutes after you'd turned off the ignition and removed the key, but not if you opened the door. As soon as you opened any door it'd turn off the radio. This to let you sit in the car listening to the radio for a while before getting out.

I guess it's kind of convenient if you want to leave the tunes playing while the people are in the car and you're in the store or something.

But it certainly adds to the challenge of figuring out just what circuit to use for adding accessories. I'd rather have the dashcam tied to whatever's keeping the radio running like that. While mine has it's own internal capacitor, to give it a little added run-time, I'd like to have a way to keep it powered without the engine being in the on position. As in, during traffic stops and the like.

My phone chargers would be fine tied to the ignition On position. But someone using their phone as a media device might prefer otherwise.

So I'm still on the hunt trying to find the ideal fuse to tie into for accessories.

 

I had a little time yesterday morning to look into the driver-side fuse box.

Well, nearly ALL of them stay powered on, full time. That is, upon opening the door and checking with a voltmeter, all but a few register ~12vdc without the ignition turned on or the engine started.

Fuse 42, labeled 'Interior Mirror' was the only non-engine circuit not powered. That and fuses 47-50 were also off until engine start. These went immediately off when the key was switched off. None lingered, like the radio does.

I've yet to experience the 30 minute interruption on the 12v sockets. But did have the opportunity to leave the driver door open for over 40 minutes and when I came back none of the circuits were powered any differently. Those that had power when I first tried still did.

Anyone know if any of the circuits in driver-side box are handled by the 30-minute timer?