12V Accessory Power Port Switches Off Erratically

[DavidAhrendts]

I have a two-way radio installed in my M3 powered by the center console 12V cigarette lighter power port. I remove the plug when the M3 is powered off so the port has no load when the car is not in use (that's so the very sensitive power management system does not switch off sensing a foreign load). Now, the accessary port is switched off for no reason at all. Might be on. Might be off.
V 9.0 (2019.20.4.2 66625e9)

David A., Los Angeles, Model 3 #9999

 

[flashflooder]

Happens to me periodically. Usually exiting, re-entering the car fixes it. Sometimes requires leaving the car alone for 20-30 minutes to allow it to take a little snooze.

No rhyme or reason to it, that I can tell.

 

[ranova]

Thats bizarre that your 12v sometimes works or doesnt work. I can only think it might have to do with the efuse tripping somehow - which resets after 20-30 minutes. The 12v socket should be able to handle 15A max load before tripping

 

[DavidAhrendts]

The M3 "rested" overnight -- port was dead. And all day at the office -- port was dead. Methinks this is now a hardware issue and will be my first trip for service! Will continue the thread.

 

[DavidAhrendts]

Thats bizarre that your 12v sometimes works or doesnt work. I can only think it might have to do with the efuse tripping somehow - which resets after 20-30 minutes. The 12v socket should be able to handle 15A max load before tripping

Right. My device would rarely get to 15A. So that's not it. I do know that the device, in it's off state, draws a meager, barely measurable 2 MA, and that is enough for the M3 girl to shut down the power port. So I pull the plug each night before she goes to sleep. Its always there in the AM. This morning -- not. Something is not right.

 

[DavidAhrendts]

Well, a discovery: there is a physical connection problem with the cigarette lighter plug. Its a clunky plug normally, but this one seems to be very picky. More to come shortly. It did light up with a twist and a push.

 

[DavidAhrendts]

A week later, and an unusual; and unexpected things has happily occurred. Just outta the blue, the power port has stayed on with the radio being plugged in continuously. Can't explain it, but I am not touching it. A fellow Tesla owner who also has a mobile radio tells me the power management system "learns." And that once trained, it will allow pretty normal operations from the power port. So again, it's working and I'm not touching anything.