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Dan, ASE Certified Technician
Category: Mercedes
Satisfied Customers: 1686
Experience:  Auto Technician
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I put new battery in now head and tail lights r flashing but

Customer Question

I put new battery in now head and tail lights r flashing but I can't turn key to start
JA: Have you checked the bulbs? Have you checked the connection?
Customer: Yes
JA: What is the model/year of your Mercedes?
Customer: S500 2006
JA: Are you fixing your S500 yourself? What have you tried so far?
Customer: Just came back after 2 months, battery was dead, put new one in and that's it
JA: Anything else you want the mechanic to know before I connect you?
Customer: Car was running perfect before
Submitted: 10 months ago.
Category: Mercedes
Expert:  Dan replied 10 months ago.

Hello my name is***** am an ASE Master Technician and I am glad to help you out with your question.

Expert:  Dan replied 10 months ago.

When you installed the new battery are you sure you did not reverse the polarity of the cables?

Customer: replied 10 months ago.
I am sure
Expert:  Dan replied 10 months ago.

Disconnect both battery cables (positive and negative) and hold them together for 15 minutes. Then reconnect one at a time, positive first then negative. This should reset the system.

Customer: replied 10 months ago.
Hi have not heard back from you
Tried again , lights r still flashing , radio etc is working , but cannot turn ignition key
Expert:  Dan replied 10 months ago.

I am thinking the computer lost the info from the key, do you have another key you can try?

This may have to be taken to the dealer to diagnose. They need to scan it for codes. Make sure to check all fuses as well.

A mobile locksmith may be able to program the key if they have the right software.

Expert:  Dan replied 10 months ago.

Check the aux battery that is in the front passengers side engine compartment near the firewall. Make sure this battery is not dead.

Expert:  Dan replied 10 months ago.

Hello again Dan here,

I am contacting you because the post has not been closed or rated.

This question is coming up on 7 days which means it will time out and close.

You have already paid to get this question answered, but you have not rated.

Let me help some more. Is there anything else I can help you with?

If I did not give you 5 star service, please let me know what I missed.