what's the difference between a 12v power outlet and the cig lighter?

here's another interesting one (i'm full of these with my old '88)...

about a year or so ago, i got xm for the jeep as my secondary radio (primary is in my jetta, which is my summer vehicle). when it first came in, i took it out of the box, and plugged the cigarette lighter adapter into the socket...no power. i look at the inside and think wow, this thing is rusted and corroded to hell...i should replace it!

so, i had my girlfriend run to autozone and pick me up a new cigarette lighter to pop in when i got home from work. she said the guy at the store told her he had problems plugging accessories into the cigarette lighter, and told her that if i still had issues i should consider getting a 12v power outlet instead.

well, after replacing the lighter socket it now works, but is a bit wacky at times...sometimes, i'll push the lighter in and my radio will shut off, as if i blew the fuse, then come right back on again. the weird thing is that through all of this, the lighter itself still works...and i never did seem to have this issue when plugging electrical accessories into the socket.

i was under the assumption that a 12v outlet is just the cigarette lighter, without the lighter element...is there something functionally different between the two? should i make the switch?

Shouldn't be any real difference between them, but.... My guess is the way the sockets are actually made. Bear with me, this is going to be a little hard to explain/imagine. The tip of the adapter is somewhat spring loaded, so it is always trying to push itself out of the socket. Some sockets are smooth on the inside, where other sockets have little slots cut in them that will actually hold the 'ears' on the adapter when you put it in the socket. You might find that rotating the adapter in the socket will make it 'lock' into the slots in the socket, provided the socket has the slots on it. Maybe this is what the guy at the store was getting at. It may have more to do with the individual manufacturer, than whether its called a cigarette lighter or power outlet.

In my 2000 the cig lighter is 12v switched/accessory, the power outlet is 12v constant. Other than that, I think they are the "basically" the same.

I asked the mechanic who does my electrical work about this. Way he explained it is that lighter sockets are designed for high amperage short term use, while electronic sockets are designed for low amperage constant use. The amperage rating on a lighter socket is a lot higher and is therefore capable of handling electronics, but you can't run a lighter off the electronics socket because it's not designed for the load.