2008 CX-9 Battery drain from BCM connector 5, pins 5J and N

[Oldschool1]

CX-9 Battery Drain on use 16

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Hi - well I recently purchased a 2008 CX- 9 knowing it had a battery drain issue - and I’ve isolated it to the “overhead light circuit and to the BMC connector 5.

Data I have:
1. As purchased, with key out and doors shut and no visible lights on - current draw is 0.4A after closing doors and then drops to 0.2A in about 1 minute and remains there constant. So 0.2A is really the continuous drain.

2. If I pull fuse #16 in the engine fuse box (overhead lights per the manual) the current drops to 0.00A (near zero)
3. Unplugging the hands free telephone module drops the current from 0.2 to 110 mA. So that device is drawing about 90 mA by itself.
4. Unplugging connector 5 on the BCM dropped the current draw from 110mA to about 20 mA
5. Tracing pins on connector 5: Pin 5J pulls 70 mA and pin 5N pulls 25 or so mA.

Does anyone know what actually to check or replace for the pin 5J “backup light signal” it seams related to a backup camera?

And any thoughts about the 5N door lock?

thx for any insight!

Oldschool1

 

[puma]

5J is a signal from the BCM(with car navigation) to the audio unit, pin 1M red/yel. I suppose it turns on the back up camera. It is only a signal between the BCM and the audio unit.

 

[Oldschool1]

Thanks for the diligent response and lead.

I have B+ voltage at the 5J pin with the ignition off and the shifter in park. According to the diagram there should be less than 1V present for this condition.

Does this point to a BCM failure? Like a FET or relay failed in the BCM (stuck in the B+ battery voltage) when it should be open, less than one volt.

However - the backup camera does turn on when the car is put into reverse ( and ignition on), so this 12 V that is present now would have the backup camera on always which isn’t the case.


Hmmm - something isn’t right here.

One possible culprit is the radio is an aftermarket Kenwood that was wired in w/o a harness adapter…and it is tapping into outputs on the BCM vs the interior fuse box. However there is no change in parasitic draw if I disconnect those 2 connections for it at the BCM. Which seems like the drain isn’t caused by the radio connection points at the BCM…..