How is the cigarette lighter supposed to work?!

[Rahul]

Hi there, my cigarette lighter is not fully working, and I am trying to understand which component might be faulty. My car is a 1971 280SL.

When I plug a modern USB charger into the lighter port, the LED on the charger is illuminated, so I am confident that it is getting power.

I have two lighter inserts that came with the car, neither of them stay recessed in the lighter port when pushed in, they both pop out and stay in their extended position. When I push them and hold them in for some period of time, it does not seem as though the elements are heating up.

Any suggestions on where I should start? I am guessing the push-in mechanisms should stay recessed when pressed, is this symptomatic of a faulty port or the push-in component(s)?

Thanks

[Tyler S]

There are 2 spring steel tangs inside the lighter socket that retain the lighter element when pushed in. Once the lighter heats up, the spring steel relaxes and the lighter pops out.
The tangs may be bent outboard from the use of power adapters. You may need to bend them back inboard a bit. Disconnect the battery or pull the fuse first.
Also the lighter filament may have expired. Authentic Classics has replacement elements.

https://www.authenticclassics.com/Mercedes-Cigar-Lighter-Element-Fits-most-1950-s-p/auth-003717.htm

[Rahul]

Just what I needed, thank you!