jdmgsr

I have a 2008 Mercedes C350 and the alarm was acting up. The key wouldn't do anything so I got into the car with the mechanical key. still nothing. I disconnected the battery and the siren was still going so I reconnected it. The siren turned off but the signals were still flashing.. two hours later when I returned the car had no power whatsoever. It wasnt the battery because I got a boost and it didnt help. But something weird is happening. One of the license plate lights is dimly lit. I think the car is in stolen mode or something like that. What the hell do I do? Is it really in stolen mode? How do i take it out? Do i have to tow it to the dealer or can I do it myself? Its not under warranty anymore because I imported the car from the US to Canada.
Thanks in advance guys!

Acapulco Bill

Sounds like a lockout between the alarm and the EIS. Others have had this problem, It is expensive to fix, the electronic modules involved aren't cheap.

Check out this thread:

https://mbworld.org/forums/c-class-w...-hate-pos.html

acr2001

There is no mode where the alarm does what you are experiencing.

You simply have a dead battery. Check with voltmeter. Repalce battery. Find out why it died.

jdmgsr

You were absolutely right.. i didnt think this was the problem since my first attempt at boosting it didn't work... thank u!

noka

A voltmeter will not always show a bad battery as it can read proper terminal voltage but not be able to deliver the proper current. It typically must be tested under load.

Acapulco Bill

@acr2001: Is the alarm programmed to sound as a warning of a pending dead battery? Or is there actually a separate source for the alarm in case someone tries to defeat the alarm system by disconnecting the battery? Just curious.

tanktube67

I'm sure your car is under warranty, have tow to the dealer or take the battery to your closest mechanic shop have them charge it and load test it to a 3rd of its cold cranking amperage depending the ambient temperature you should be getting a result of 9.6volts. The car alarm has its own battery, even if you disconnect the battery the alarm still will go off, just another safety MB burglary feature.