Replacing battery: Maintain power or not?
MBWorld Fanatic!




Joined: Aug 2003
Posts: 8,881
Likes: 1,211
From: In my garage
E55, GLS450, GL63, GLE350
Trust me, the carpet on my X166 GL63 did not need to be cut. The install was a bit more difficult getting the ventilation tubing plate back in but, again, did not require cutting. The hole is of ample enough size for me to get the old battery out and new battery back in place.
I did say "I do not know about X166/X164". This is W166 forum and this is an other reason why W166 board should not be combined with X166 (a separate and not related topic).
I know dealers when changing/servicing battery in W166 ML/GLE "cut" carpet (cutting is very easy and makes a difficult without cutting job easier). There's someone in W166 ML forum who changed the battery without cutting carpet.
If anyone is interested, this is the link:
https://mbworld.org/forums/m-class-w...t-cutting.html
I know dealers when changing/servicing battery in W166 ML/GLE "cut" carpet (cutting is very easy and makes a difficult without cutting job easier). There's someone in W166 ML forum who changed the battery without cutting carpet.
If anyone is interested, this is the link:
https://mbworld.org/forums/m-class-w...t-cutting.html
Last edited by threeMBs; Jul 15, 2021 at 05:37 PM.
MBWorld Fanatic!




Joined: Aug 2003
Posts: 8,881
Likes: 1,211
From: In my garage
E55, GLS450, GL63, GLE350
Will check my GLE this weekend. Do not see the battery compartment under the seat as being any different than my X166 GL but can't tell with certainty until I check. However, the rear battery in my X166 GL63 is in a slightly different location than the X166 GLE. Very close but is different.
Some people say they've replaced a W166 battery without cutting the carpet. In my recent experience I found the carpet to be baggy and I might've been able to 'tent it' taut with a slat and worked the battery out without cutting the carpet, especially if I was not maintaining power and worried about the positive terminal touching anything.
But I was maintaining power (the crux of this entire thread in the first place) so I decided to make the carpet cuts. The cuts only needed to be about 3" long and there is already a crease where you need to cut. It was easy to do with a sharp knife (I used a utility knife).
But I was maintaining power (the crux of this entire thread in the first place) so I decided to make the carpet cuts. The cuts only needed to be about 3" long and there is already a crease where you need to cut. It was easy to do with a sharp knife (I used a utility knife).
Last edited by sams_6; Jul 27, 2021 at 04:16 AM.
kajtek1,
I believe the radio code is on a little card included with the original manuals. But if you don't have that your options are:
1) be at the mercy of a dealer to provide the code to you
2) remove the radio and see if there is a serial number decal on it
I agree that resetting the steering sensor by turning the wheel lock-to-lock a few times, and retraining the windows and sunroof only takes a minute or two. Does anyone know with certainty if there's a risk of the radio requiring a reset on a W166 if the battery is disconnected?
Your experience with your 2014 E-Class suggests that things are likely to go smoothly even if disconnecting the battery. But I'd like to hear from someone with specific W166 knowledge or experience. It seems several readers are interested in learning this.
I believe the radio code is on a little card included with the original manuals. But if you don't have that your options are:
1) be at the mercy of a dealer to provide the code to you
2) remove the radio and see if there is a serial number decal on it
I agree that resetting the steering sensor by turning the wheel lock-to-lock a few times, and retraining the windows and sunroof only takes a minute or two. Does anyone know with certainty if there's a risk of the radio requiring a reset on a W166 if the battery is disconnected?
Your experience with your 2014 E-Class suggests that things are likely to go smoothly even if disconnecting the battery. But I'd like to hear from someone with specific W166 knowledge or experience. It seems several readers are interested in learning this.
I changed my battery in w166 ML63 MY14, DID NOT use remote power source to the car while changing the battery as per the previous comment, no issues, everything worked as per normal on start up. Importantly put the seat all the way forward and up as far as it will go, hardest part is lifting out the old battery.
I have had my ML63 for 8 years and got used to the terrible lag. last time i changed the battery 7 years ago I kept power to the car while i changed the battery, fearing the memory would be lost. i have now replaced the battery again, but this time without power to the car, having read Forum suggesting it wasn't required (and without any issues at all). With new battery fitted OMG the flat spot seams mostly gone (or is this a placebo effect?) so my advice to those with the flat spot, disconnect the battery for a couple of minutes and see if there is any improvement.
Yes I have done the transmission reset on a few occasions. While it does forget your driving technique. It doesn’t take away the flat spot lag.
After replacing this battery this time it’s been a significant improvement
After replacing this battery this time it’s been a significant improvement





