john maddox

Can the 12 volt socket in the trunk be permanently switched on - mine turns off when the ignition off but I want it to stay on to charge ipod etc when parked.

Anyone found a way for this - I read that on sedans a fuse could be moved to another position to make power permanent.

Thanks all

fdriller9

I wouldn't suggest doing that. You can drain your battery if you forget to unplug it for an extended period of time.

There is no easy way to convert the existing switch to an always on outlet.

You can however, go to Radio Shack and buy a cigg lighter adapter that has exposed wires for connecting to a battery. Ground to a bare metal location, and pick up a fuse tap kit from Auto Zone so you can just tap a fuse location that is always on. You will need to either do trial and error to find out witch fuse locations will stay on after ignition is switched off. Or use a multimeter to measure voltage.

I'm not sure about Mercedes Benz, but I am very familiar with BMWs and know that the fuse panels are on user activated circuits. They will shut off and go to sleep after an extended period of inactivity. They will only wake when either a door is opened, car is locked/unlocked, or another module activates them, say to check the status of a component.

If Benz' are the same as BMWs, tapping power from the fuse location will prevent battery discharge. If not, you will need to tap power directly from the battery but you risk draining it. You MUST fuse the power line close to the battery if you choose to run it directly off the battery. A 5A fuse should do it. You can get inline fuse holders at most auto parts stores.

iankayem

The rear console socket and the load compartment socket are both "live" without the ignition on!

However you cannot just plug and go - you must apply the load then turn on the ignition, (not just accessory), let the ipod or whatever work, then you can turn off the ignition and lock the car with the current flowing.

There is a voltage safety cutout which will trip the flow to preserve the battery for starting etc.

I permantly have a security camera in the rear console, and I have had the Engel car fridge in the back, and never yet had them shut off.

The socket in the front console only functions in accessory or ignition settings.

john maddox

Thanks for your replies - especially Ian. I have just done as you say and my ipod is happily charging in the trunk as we speak !!

I originally plugged it in and expected it to charge immediately. As soon as I ran the engine and turned off it worked fine.

Thanks again.

N4HHE

For 3.5 years I thought my aux 12V outlets automatically shut off shortly after turning off the ignition. Counted on it for turning off my Garmin GPS (which I much prefer over the built-in "nav" system).

Then earlier this week I replaced the original 12V battery and my outlets no longer shut off automatically. Is there a way to do the opposite of what John asked, to make my outlets turn off with ignition?

Re-reading the owner's manual I see aux outlet off is a safety feature which activates when the 12V battery is low. Apparently mine has been low for a long time.