ok so i'm still none the wiser after reading a bunch of threads on this.
I'm UK, me and my dad have Boxster S's. Mine (2002, facelift) has power all of the time, my dads, a 2000, doesn't and only powers up with ignition.

so, maybe it is a facelift thing? maybe previous owners have changed it....?


either way... is there a way of stopping the power all of the time? i, like OP, don't much fancy the idea of the device plugged into the lighter (in my case, a BT/FM transmitter thing) draining the battery.

The factory set the cars up for constant power from the factory to allow the use of a battery maintainer with the car locked up and the alarm on.

ok, i mean i can kinda understand that for fancy cars, but a boxster? at the price they were selling for? hardly reason to keep it in the garage not being used :)

is there a way to disable then?

$50k+ for a 986 was a lot of money 20 years ago, and it still is today, the majority of 986's bought new where weekend warrior/garage queens. If you want switched power use the phone plug under the center console instead of the lighter, it is easy to tap into directly or you can use some wire taps and add a second hidden lighter plug under the center console to plug into. Changing the lighter to switched power would require a lot more work/wiring.

RHD cars made before 2001 have the cig lighter on a relay (on with ignition).
LHD cars made before 2001 have the lighter always powered.

2001 and up, all are powered constantly except for Australian market cars.
That's all I could extract from the wiring diagrams.

ah man, I don't know if i can be digging around under the console just to get switched power, i need the device 'to hand' rather than hidden away.

whats the chances of a device like a bluetooth fm transmitter sitting there on idle killing the battery from a few days of non use at a time? obviously i'll try to remember to unplug it if i know the car isnt going to be used for a substantial amount of time.

You could do it at the fuse box.
Using a jumper wire with a spade on one end and a fuse tap on the other, insert the spade into the the unpowered side of fuse D5 (for the lighter), and use the fuse tap on a switched power fuse that can handle the additional load.

I came across a video on YouTube ( it has English subtitles ) that achieves the same thing mentioned here. Seems like a reasonable way to solve the problem: https://youtu.be/vgE-5sXXbAs?si=V-XY6EhGOBGKyQLT