I just had to change the battery in my 2013 ML350 4Matic and here is what I learned. Here are the official instructions to replace the battery:
LINK TO PDF INSTRUCTIONS
What follows are partial instructions that supplement the instructions in the above PDF - in other words, the comments below are not all the instructions, you will need to read the PDF also.
IMPORTANT - after you change the battery you will need to reset the ECU as described in Step 8 below or the car will start but you will not be able to switch out of park.
(1) You cannot change the battery unless you have power to the car because you have to move the seat forward and back several times to change the battery. This means you either need a jump, a jump pack, or some battery power left in the battery to supply power to the car while you are doing this change.
(2) You do not need to cut the carpet as described in the instructions. There is enough play in the carpet that you can slide the battery out and the new one in without cutting the flap out in the carpet. It would be easier to cut the carpet to get the battery in and out, but not necessary
(3) Loosen the forward positive terminal first, but leave it connected to the positive battery terminal. After you loosen the forward positive battery terminal, slide the seat all the way forward and up.
(4) After you disconnect the rear ground terminal, from the back reach forward under the carpet and pull the positive battery connection up and to the right out of the way.
(5) Tuck the battery vent tube and the negative terminal behind metal flanges in the battery box so they do not get damaged when you slide the old battery out and the new battery in.
(6) You will need a 13mm socket and a long extension to remove the rear battery hold down bracket - this is the only bracket that hold the battery down. When you slide the new battery in and need to reconnect the hold down bracket, you will need that 13mm socket, long extension, and shove a piece of paper in the socket to hold the nut in the socket so you can reach the threads in between the battery and back wall of the battery box. You cannot reach the threads without using the paper-in-socket-to-hold-the-nut technique.
(7) You will need to re-install the battery box cover. The battery box cover has the rear AC vent attached to it on the top with one plastic push pin. You need to remove the push pin, then remove the vent, then install the cover by itself, then slide in the vent on top the battery box cover and connecting to another vent to the left, then slide the seat all the way back and from the front you need to reach under the seat and carpet and reinstall the push pin from the top. First put the outer pin in the hole, then push the push-pin into the outer pin
(8) After you are finished reinstalling the new battery you now need to reset the ECU or your ML350 will not switch gears out of park. I cannot believe that this is not in the owner's manual. Here are the steps to reset the ECU:
- If you have Keyless Go, pop off the Keyless Go button
- Insert the key
- Turn the key to "ON" - not start - and leave it "ON" for more than 2 minutes
- Turn the key to "OFF", but leave the key "IN" for at least 10 seconds
- After at least 10 seconds, turn the key to "ON", push and hold the brake, turn the key to "START" and the car should start. Verify that you can switch gears.
- If you have Keyless Go replace the Keyless Go button
That's it.
The battery you need is model Duralast H8-AG available here priced at $183.99 from Autozone:
http://www.autozone.com/batteries-st...930123_0_3896/
This Duralast AGM battery is the identical battery as the Mercedes OEM battery - both batteries come off the same line at a Johnson Controls-owned factory. Two local Mercedes dealers wanted $249.99 for the same battery with Mercedes stickers on it (and both dealers gave me attitude about changing my own battery and told me I could not do it). One Mercedes dealer quoted me $565 to change the battery, battery included - what a deal!
With these supplemented steps it is not rocket science to replace the battery.
LINK TO PDF INSTRUCTIONS
What follows are partial instructions that supplement the instructions in the above PDF - in other words, the comments below are not all the instructions, you will need to read the PDF also.
IMPORTANT - after you change the battery you will need to reset the ECU as described in Step 8 below or the car will start but you will not be able to switch out of park.
(1) You cannot change the battery unless you have power to the car because you have to move the seat forward and back several times to change the battery. This means you either need a jump, a jump pack, or some battery power left in the battery to supply power to the car while you are doing this change.
(2) You do not need to cut the carpet as described in the instructions. There is enough play in the carpet that you can slide the battery out and the new one in without cutting the flap out in the carpet. It would be easier to cut the carpet to get the battery in and out, but not necessary
(3) Loosen the forward positive terminal first, but leave it connected to the positive battery terminal. After you loosen the forward positive battery terminal, slide the seat all the way forward and up.
(4) After you disconnect the rear ground terminal, from the back reach forward under the carpet and pull the positive battery connection up and to the right out of the way.
(5) Tuck the battery vent tube and the negative terminal behind metal flanges in the battery box so they do not get damaged when you slide the old battery out and the new battery in.
(6) You will need a 13mm socket and a long extension to remove the rear battery hold down bracket - this is the only bracket that hold the battery down. When you slide the new battery in and need to reconnect the hold down bracket, you will need that 13mm socket, long extension, and shove a piece of paper in the socket to hold the nut in the socket so you can reach the threads in between the battery and back wall of the battery box. You cannot reach the threads without using the paper-in-socket-to-hold-the-nut technique.
(7) You will need to re-install the battery box cover. The battery box cover has the rear AC vent attached to it on the top with one plastic push pin. You need to remove the push pin, then remove the vent, then install the cover by itself, then slide in the vent on top the battery box cover and connecting to another vent to the left, then slide the seat all the way back and from the front you need to reach under the seat and carpet and reinstall the push pin from the top. First put the outer pin in the hole, then push the push-pin into the outer pin
(8) After you are finished reinstalling the new battery you now need to reset the ECU or your ML350 will not switch gears out of park. I cannot believe that this is not in the owner's manual. Here are the steps to reset the ECU:
- If you have Keyless Go, pop off the Keyless Go button
- Insert the key
- Turn the key to "ON" - not start - and leave it "ON" for more than 2 minutes
- Turn the key to "OFF", but leave the key "IN" for at least 10 seconds
- After at least 10 seconds, turn the key to "ON", push and hold the brake, turn the key to "START" and the car should start. Verify that you can switch gears.
- If you have Keyless Go replace the Keyless Go button
That's it.
The battery you need is model Duralast H8-AG available here priced at $183.99 from Autozone:
http://www.autozone.com/batteries-st...930123_0_3896/
This Duralast AGM battery is the identical battery as the Mercedes OEM battery - both batteries come off the same line at a Johnson Controls-owned factory. Two local Mercedes dealers wanted $249.99 for the same battery with Mercedes stickers on it (and both dealers gave me attitude about changing my own battery and told me I could not do it). One Mercedes dealer quoted me $565 to change the battery, battery included - what a deal!
With these supplemented steps it is not rocket science to replace the battery.
