GL X164 Strange Battery Drain

[MGSED37]

Hi All,
I'm still working on this issue but it has been with the car now for a while.
When the weather is cold, after two to three days, the car won't start. It's a GL420 X164. Keyless system, so press the button, solenoid engages then..... click click. charge for ten mins, off we go.
I've checked, door handles for water ingress, Rear SAM looks ok but not fully checked, Infortainment system pulls 1.3 amps then shuts off as expected when locked. Just wondering if anyone has any ideas at all?

Things I've pondered on:-
Seat controllers, as sometimes when you get in the car, the seat has inflated it's bolsters - apparently on its own .... but I do have two young lads who like to press buttons! I do have two seat controllers which I can change but haven't done it yet.
Airmatic - Sometimes I hear the thing self adjust when locked, is this normal? could this be doing it? and can it be stopped?

I'll continue to push on with it but any ideas etc would be appreciated. And of course I'll update as I go.

All the best, and thanks for your help.

 

[Bobby Dazzler]

Do you have COMAND or reversing camera?

When my COMAND failed - and got stuck in a repeated boot up cycle whilst driving - I suspect that it occasionally remained “active” with sound, lights or display, even though the ignition was off, and it flattened the battery. After I had COMAND repaired it never did return.

However the twice it was jump started, the reversing camera didn’t work. The first time I replaced the reversing camera module. The second time I didn’t. Both times, Mercedes and Mobilo said that the camera may be the cause rather than a symptom of jumpstarting.

It also happened a couple more times but I tried to use the car before it was completely flat, so I was able to charge the battery. It’s not happened from perhaps 6 or 7 years, and whilst I’m not sure whether it was the camera module or COMAND, I’m fairly sure one of them was the cause!

 

[MGSED37]

Do you have COMAND or reversing camera?

When my COMAND failed - and got stuck in a repeated boot up cycle whilst driving - I suspect that it occasionally remained “active” with sound, lights or display, even though the ignition was off, and it flattened the battery. After I had COMAND repaired it never did return.

However the twice it was jump started, the reversing camera didn’t work. The first time I replaced the reversing camera module. The second time I didn’t. Both times, Mercedes and Mobilo said that the camera may be the cause rather than a symptom of jumpstarting.

It also happened a couple more times but I tried to use the car before it was completely flat, so I was able to charge the battery. It’s not happened from perhaps 6 or 7 years, and whilst I’m not sure whether it was the camera module or COMAND, I’m fairly sure one of them was the cause!

Many thanks for your reply, very much appreciated. It does have an NTG 2 unit with reversing camera. What I can say is that my wife accidentally smashed the screen on the original unit and I had to source another. I put this unit in and coded the camera. It has drained the battery with the original and the refurbished unit, but I haven't checked the camera, I shall certainly check this out thank you. Keep the ideas coming

 

[Bobby Dazzler]

Many thanks for your reply, very much appreciated. It does have an NTG 2 unit with reversing camera. What I can say is that my wife accidentally smashed the screen on the original unit and I had to source another. I put this unit in and coded the camera. It has drained the battery with the original and the refurbished unit, but I haven't checked the camera, I shall certainly check this out thank you. Keep the ideas coming

I hope you get to the bottom of it soon

 

[MGSED37]

I hope you get to the bottom of it soon

Many thanks. I think I might get it in work next week and have a good go at it again. I'll keep you posted

 

[MGSED37]

So bit of an update. Wednesday, the car had been left overnight and next day flat. I say flat, battery was reading 11.98volts. But this device was going off constantly "Dynamic Seat Vacuum Pump" I've attached a photo and is situated in the N/S rear inner wing. It buzzes, randomly when the car is open. And apparently it was going off like mad Wednesday night whilst my youngest was sat in the back of the car. Part number 000 800 25 48. Does anyone have an idea where this pump or unit feeds and is fed from? Million dollar question I know. Any help greatly appreciated. I'll keep you posted, tune in next time for another episode of pure brilliance as if lol!