2012 GL450 dead battery
03-08-2014, 09:38 AM
#1
Junior Member
Thread Starter
2012 GL450 dead battery
I found an issue that’s has caused me a dead battery a few times. For example, my GL had had been parked for over an hour with the key out of the ignition. I was in the garage and heard a faint noise of a fan running, so looked inside the car and saw the red light on the center dash climate control lit for the rear heater. I opened the door and turned it off. I'm hoping someone might have seen this before.
03-20-2014, 11:21 AM
#2
Junior Member
Thread Starter
Resolution for battery issue
Here's an update which hopefully will help someone else in the future. I took the car into my friendly independent mechanic and learned some interesting stuff about the car and the issue.
First, the battery was described a "glass mat type" (as in containing internal matting), not a traditional design with a bunch of liquid acid floating around. Used because the battery is under the front seat and when installed goes in at a really steep angle, plus we don't want acid
leaking inside the passenger compartment. Secondly, these batteries once they go dead might as well go in the trash. My GL was a salvage, and the battery was dead when it was pulled off the car carrier when delivered to me. The mechanic said he's never been able to get one back to normal once they discharge completely. Also my experience because I had the same type of battery in my plane.
He didn't recommend a trickle charger on these types of batteries and I've seen several posts on this site about trickle charging, so beware.
On another note, he asked me did I notice a low battery after using the
tailgate. Of course we use it all the time, so the answer was yes.
Mercedes has a SAM module that controls the tailgate, so if the doors and
tailgate are opened in a specific sequence then the computer gets confused and remains lit; thus, draining the battery. This defect mainly impacted the earlier x164's. However, he hooked the car to the mother ship in Germany and downloaded an update, so Mercedes must have found something in the code to fix.
Finally, the thing that I mentioned in the original post about finding the fan blower running after the car is off is actually by design. Done to dry
the A/C evaporator to keep mold from growing and causing the car to stink of mold with the A/C running.
Hope that helps.
First, the battery was described a "glass mat type" (as in containing internal matting), not a traditional design with a bunch of liquid acid floating around. Used because the battery is under the front seat and when installed goes in at a really steep angle, plus we don't want acid
leaking inside the passenger compartment. Secondly, these batteries once they go dead might as well go in the trash. My GL was a salvage, and the battery was dead when it was pulled off the car carrier when delivered to me. The mechanic said he's never been able to get one back to normal once they discharge completely. Also my experience because I had the same type of battery in my plane.
He didn't recommend a trickle charger on these types of batteries and I've seen several posts on this site about trickle charging, so beware.
On another note, he asked me did I notice a low battery after using the
tailgate. Of course we use it all the time, so the answer was yes.
Mercedes has a SAM module that controls the tailgate, so if the doors and
tailgate are opened in a specific sequence then the computer gets confused and remains lit; thus, draining the battery. This defect mainly impacted the earlier x164's. However, he hooked the car to the mother ship in Germany and downloaded an update, so Mercedes must have found something in the code to fix.
Finally, the thing that I mentioned in the original post about finding the fan blower running after the car is off is actually by design. Done to dry
the A/C evaporator to keep mold from growing and causing the car to stink of mold with the A/C running.
Hope that helps.
