Brief history - I bought a 2000 E320 in May 2011. Only drove it 325 miles as it stays garaged (big mistake I found out). Last week I attempted to start it and it was DEAD! Both ignition keys would not turn. Displays were blank.
Nothing!!
Things I've attempted to date.
- Charged battery through under the hood posts with neighbor's charger.
- Charged battery directly with neighbor's charger.
- Took battery to local car shop for overnight charge.
- Purchased new battery from Autozone.
Nothing works! I've read all the threads on this subject. Before I have it towed to a repair shop, am I missing something?
I do not qualify for the new road assistance program since I haven't spent $100 before this incident.
Any suggestions?

 

I believe you would need to provide a much better description before getting an internet diagnosis. Even knowing if it's crank/no start, no crank/no start, other items on the car work/don't work, etc.

 

I assume old battery had failed so any charging effort did not produce enough voltage to engage starting cycle.

Was new battery fully charged before you tried using it? A W210 requires a MINIMUM voltage to engage starting cycle. Less than about 12v and it will not even try although you should see instrument cluster lights. If no lights, then maybe a problem with ECU. So a scan with the SDS is probably in order.

Just a thought. When you took your old battery to the shop they should have done a load test and confirmed that it would hold a charge. If they don't know that maybe you need a better shop. Be sure to tow the car to a shop (dealer?) which has an SDS. FYI, if you had purchased a OEM battery from 1-800-FOR MERCedes they would have come to you and installed it and you would have then qualified for free towing. Yes, I know, hindsight is 20-20.

Hope this helps you some.

You are right that ALL cars benefit from being driven regularly.

 

Hey there, sorry to hear about your troubles.
Was the new battery appropriate for your car? Had the authorized technicians installed it for you and run appropriate test to see it is working normally?

The more you drive, less problems you face. I used to have a second garage car for occasional driving. Damn it. It used to cause more problems than the one I drive every day.