PatchesC300

Did many searches on this and did not find a definite answer. Dealer told me that i need to replace my second battery for the computer and wanted to charge me $368. I asked where this second battery is and she said might be in the trunk or under the seat. I am only aware of 1 battery on the passenger side in upper corner. I declined the battery change because I thought they were really talking about the main battery and I knew i did not need it.

For a background, I took my car in because it would not start because of the EIS issue. They are changing both the EIS and ESL. I did find many threads on this, and found that the odds of both going bad are rare, but they do push you to change both. I also asked if there were indeed faults found on both the EIS and ESL and she said yes. Not sure if I was taken or not. Let me know your thoughts.

PatchesC300

Is this a bad question? I did searches, but no definite answer. Please let me know if I am out of line asking this. I do not want to be THAT GUY asking a stupid question. If this has already been answered I could not find it so please give me the link to were the answer is. Thanks

Skyline45

Nah, not a stupid question. Unfournatley I'm in the same boat as you. I'm only aware of the battery on the passenger side under the hood. However, my battery died on me about a month ago and all my computer settings saved. So it could have another battery somewhere..

Although with knowing how computers work, I don't see how this battery could go bad unless you're having other electric problems which you mentioned. Computers don't need nearly the same amps that are required to start a car. ....At least the effective ones don't...

capt_paul

On my car (2013 C350), I have two batteries; 1 located I the back passenger side of the engine compartment, as well as the auxiliary battery located in the trunk. If you lift up on the trunk liner, you will see a black plastic box covering the aux battery, if you indeed have a second battery. It is much smaller than the primary battery and it is used for supplementing the main battery.

Out of curiosity, why do you doubt the service technician's statement that you need to replace the auxiliary battery?

PatchesC300

Thanks Skyline and Capt. Paul.
It was the service writer not the service tech that told me I needed to replace the second battery. When I asked her where exactly it was located she could not tell me. She just said maybe the trunk, but wasn't sure. I know they work on commission and I know they are forced by management to upsell people.