Dealer says 12V is draining battery - Is that true?

Six Speed Stephen · 2026-11-01T12:57:46-0600

I have a Uniden R7 plugged into the 12V socket behind the center arm rest - My dealer is saying that the radar detector is draining the battery when the car is off - but the Emira manual says that the 12V turns off when the car turns off - Just like the rear mirror USB for my dash cam.

Does anyone know if it's possible the 12V is still drawing power when the car is off? Anyway/how can I measure that?

Thanks!

kitkat · 2026-11-01T13:15:50-0600

The 12V socket and the USB on the mirror are on CR04 logic and not KL15 logic. KL15 is only active while the ignition is on but the CR04 has it’s own logic. It clearly stays on for some time after the car has been turned off, but it immediately switches to off when the car is locked.

mr.suntorytime · 2026-11-01T13:27:25-0600

can confirm. my dashcam plugged into the upper usb on mirror stays powered until car is locked.

Six Speed Stephen · 2026-11-01T15:25:56-0600

kitkat said:
The 12V socket and the USB on the mirror are on CR04 logic and not KL15 logic. KL15 is only active while the ignition is on but the CR04 has it’s own logic. It clearly stays on for some time after the car has been turned off, but it immediately switches to off when the car is locked.

Got it - So the battery issues should not be related to having the dash/radar plugged in after locking the car, right?

I also did some forum searching and a failing battery doesn't seem super uncommon. Perhaps its just defective