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Why isn't my new cigarette plug car adapter working? Answered

I just got an Enercell 12V 2A car adapter. However, it wasn't powering the device I wanted to use it for. I got out my multimeter and did some testing: the socket itself produces power, but the plugged in adapter does not. The weird thing is that I tested it before with the car running and it worked. Is there some special way to plug this thing in that I'm not aware of? Any help would be appreciated.



Best Answer 7 years ago

Seconded what fram says -- check the ignition.

If it's definitely got power in the socket but no power coming out the wire it's one of two things (which are ironically the same thing)
1) a wire is broken and it's open circuit, no voltage. Check for continuity between + to + and - to - on the adapter itself using your multimeter.
2) the fuse blew, and (technically) a wire is broken, same as #1. Check the fuse, most plug adapters like these have one. Try unscrewing the plastic shroud over the metal tip of the adapter.

Since it is a 12 volt to 12 volt adapter it likely has no internal circuitry/regulation mechanism.

I figured it out: it was the fuse. Thanks!

Back when i was young... in the olden days... the cigarette plugs in cars were wired to always be "ON". Nowadays, they are wired through a relay that is only on if the car ignition is "ON". This helps assure you don't drain the battery with items plugged into the cigarette lighter plug and the motor not running. However it adds the disadvantage of not being usable unless you turn on the ignition key. This may not be true with ALL cars, but generally i think this is probably the situation you are frustrated about.


In Europe at least, its still optional - one car we have is permanently ON, the other on only with the ignition, so as they say YMMV.

And in some vehicles, there is one contact in the connector which is always on, and another which is switched !!


. I was surprised to find out that my 2009 Nissan was that way - ignition off = no power to cigarette lighter receptacles. Luckily, the cell phone I keep in the glove box will stay charged even though it only charges when I'm driving.