Auxilary Battery Malfunction
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Junior Member
Joined: Jun 2017
Posts: 26
Likes: 1
2015 GL 450
Auxilary Battery Malfunction
I have 2015 GL 450 and getting an Auxiliary battery malfunction. I think this battery needs to be swapped out.
Are these normally covered under extended warranty? If not, how much do these run for for parts and labor?
Are these normally covered under extended warranty? If not, how much do these run for for parts and labor?
Senior Member
Joined: Jul 2007
Posts: 283
Likes: 102
From: Maryland
S 550, S65 Coupe
I Just replaced mine over the weekend by myself. I bought the Battery from FCP Euro for $50. All I had to do was remove the sill by the rear hatch ( 2 torx and then just pull up to free the clips). Then lift out the tray with the Spare tire tools, The gray cloth lining below that needs to be moved to get access to the battery by removing the 2 black pins on the right side and you can fold it back out of the way. The battery is right there to the right in a bracket. Just need a 10MM socket on an extension to remove the bolt and it comes right out. Then replace the battery and put everything back together. Think it took all of 5 min start to finish. Really easy if you are even slightly mechanically inclined.
Last edited by Jim Ma; Feb 8, 2021 at 02:02 PM.
Member
Joined: Dec 2006
Posts: 207
Likes: 17
From: Captiva Florida
14 GL 350, 23Chevy Bolt EV and 22 EUV
My 7 1/2 yr old GL 350 needed prophylactic replacement of both batteries. The auxiliary I did myself, followed Jim Ma’s advice. Battery arrived in 4 days, replacement was 15-20 min without incident.
I think I’m going to the local Indie shop for Main Battery replacement.
I think I’m going to the local Indie shop for Main Battery replacement.
Junior Member
Joined: Dec 2003
Posts: 72
Likes: 0
From: Vancouver, BC
2013 GL350 Bluetec
curious how do i know if my Aux battery is dead? i just changed my main battery and car still won't start. This is on my 2013 GL350.
IF Aux battery is dead, does it usually have a warning message on dash?
thanks in advance.
IF Aux battery is dead, does it usually have a warning message on dash?
thanks in advance.
Member
Joined: Dec 2006
Posts: 207
Likes: 17
From: Captiva Florida
14 GL 350, 23Chevy Bolt EV and 22 EUV
Error codes, erratic behavior in electronics, and the like. I wanted to avoid these potential problems on a 7 1/2 year old battery.
Sams Club will replace my main battery with a Duracell AGM H 8 next week, ~ $ 180.00.
Sams Club will replace my main battery with a Duracell AGM H 8 next week, ~ $ 180.00.
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Joined: Oct 2009
Posts: 7,018
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From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
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Joined: Aug 2015
Posts: 10
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C250
all screws removed but couldn't get the battery/bracket off
Hi guys, also have a 2015 GL450, auxiliary battery looks to be dead...
I was able to get to the bracket post the 2 black pins, then removed the bolt to get the metal piece holding down the battery.
Then removed the 4 nuts - 2 on the left/front side of the battery, 1 in the back/bottom, and then 1 bolt to the back side ... so 3 on the floor, 1 on the back (tail light side).
I also removed the +/- out and pulled the vent plug out. That's when I ran into trouble... the "screws" are pretty long, so I was able to get the bracket out in the front (where the 2 on the floor, either front side of car or left side of battery looking at it in the trunk), but was unable to get the back 2 parts of the bracket from the screws (the bracket itself hit some metal piece, so I couldn't pull it up far enough to get it off the bottom bolt or the bolt coming from the tail light side. What did I do wrong? Please help... can't believe I'm contemplating taking my car in somewhere to get a battery changed...
and one more thing, from Jim's post, it sounds like he got the battery out after just removing the bracket holding it down... and the +/- ..? no clue how thats possible with the space limitations...
I was able to get to the bracket post the 2 black pins, then removed the bolt to get the metal piece holding down the battery.
Then removed the 4 nuts - 2 on the left/front side of the battery, 1 in the back/bottom, and then 1 bolt to the back side ... so 3 on the floor, 1 on the back (tail light side).
I also removed the +/- out and pulled the vent plug out. That's when I ran into trouble... the "screws" are pretty long, so I was able to get the bracket out in the front (where the 2 on the floor, either front side of car or left side of battery looking at it in the trunk), but was unable to get the back 2 parts of the bracket from the screws (the bracket itself hit some metal piece, so I couldn't pull it up far enough to get it off the bottom bolt or the bolt coming from the tail light side. What did I do wrong? Please help... can't believe I'm contemplating taking my car in somewhere to get a battery changed...
and one more thing, from Jim's post, it sounds like he got the battery out after just removing the bracket holding it down... and the +/- ..? no clue how thats possible with the space limitations...
Last edited by nycrx7; Aug 18, 2023 at 04:01 PM.
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Newbie
Joined: Jan 2024
Posts: 2
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2016 gl 450
Same issue as nycrx7
Having the same issue with my 2016 GL 450. Have the large auxiliary battery located in rear wheel well. Seems to not have enough room to remove the harness or battery. Some guidance would be wonderful.
Hi guys, also have a 2015 GL450, auxiliary battery looks to be dead...
I was able to get to the bracket post the 2 black pins, then removed the bolt to get the metal piece holding down the battery.
Then removed the 4 nuts - 2 on the left/front side of the battery, 1 in the back/bottom, and then 1 bolt to the back side ... so 3 on the floor, 1 on the back (tail light side).
I also removed the +/- out and pulled the vent plug out. That's when I ran into trouble... the "screws" are pretty long, so I was able to get the bracket out in the front (where the 2 on the floor, either front side of car or left side of battery looking at it in the trunk), but was unable to get the back 2 parts of the bracket from the screws (the bracket itself hit some metal piece, so I couldn't pull it up far enough to get it off the bottom bolt or the bolt coming from the tail light side. What did I do wrong? Please help... can't believe I'm contemplating taking my car in somewhere to get a battery changed...
and one more thing, from Jim's post, it sounds like he got the battery out after just removing the bracket holding it down... and the +/- ..? no clue how thats possible with the space limitations...
I was able to get to the bracket post the 2 black pins, then removed the bolt to get the metal piece holding down the battery.
Then removed the 4 nuts - 2 on the left/front side of the battery, 1 in the back/bottom, and then 1 bolt to the back side ... so 3 on the floor, 1 on the back (tail light side).
I also removed the +/- out and pulled the vent plug out. That's when I ran into trouble... the "screws" are pretty long, so I was able to get the bracket out in the front (where the 2 on the floor, either front side of car or left side of battery looking at it in the trunk), but was unable to get the back 2 parts of the bracket from the screws (the bracket itself hit some metal piece, so I couldn't pull it up far enough to get it off the bottom bolt or the bolt coming from the tail light side. What did I do wrong? Please help... can't believe I'm contemplating taking my car in somewhere to get a battery changed...
and one more thing, from Jim's post, it sounds like he got the battery out after just removing the bracket holding it down... and the +/- ..? no clue how thats possible with the space limitations...
