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Pete
Pete, Mercedes Mechanic
Category: Mercedes
Satisfied Customers: 24707
Experience:  Over 15 years experience as a Mercedes dealer technician
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I just changed battery in 2006 cls500 and it still isnt

Customer Question

Hi i just changed battery in 2006 cls500 and it still isnt turning over. Does auxlary battery need to be changed also for car to start up
Submitted: 9 months ago.
Category: Mercedes
Expert:  Pete replied 9 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

Your starter operates off of the main battery.The small auxiliary battery is a back up battery for your models brake system so the auxiliary battery will not cause the no start issue here.

Are the electronics powering on in the vehicle and all operating o.k. when this issue occurs and is it the starter is not engaging to turn over the engine?

Do you hear a click or any other noise from the engine area when trying to start the vehicle?

Let me know so we can continue,thanks Pete.

Customer: replied 9 months ago.
Electronics are coming on but car isnt trying to turnover..
Expert:  Pete replied 9 months ago.

I have tried to accept the phone call request but it looks like payment may have been denied.

In your under hood fuse panel locate the starter relay as seen here https://www.dropbox.com/s/vmw4r9q2nyysp8k/start-02-12.gif?dl=0.Have someone try and start the engine and feel this relay to see if it is felt to click.If it is then the starter motor itself is most likely at fault needing replaced.If it does not click try tapping on the relay while someone is trying to start the car and see if the engine starts.If it does then this relay needs replaced.If it does not click and tapping does not work then the signals to this relay need tested with a multi meter to see which signals are present as this can be an issue with the electronic ignition switch (EIS) at fault here needing replaced which is the switch your key inserts into.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 9 months ago.
I do hear a click click noise now
Expert:  Pete replied 9 months ago.

Can you tell where it is coming from at all?Have you checked the relay to see if it is clicking?

If the noise is coming from the lower side of the engine this indicates the starter itself is at fault and needs replaced.This is a common component to fail.If the click is coming from the relay most likely this is the starter as well as this generally indicates the start signal is present and relay is o.k.

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.

Thanks Pete