C-Class (W203) 2001-2007, C160, C180, C200, C220, C230, C240, C270, C280, C300, C320, C230K, C350, Coupe

C 240 alarm sounding and fog lights flashing randomly

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Old Jan 13, 2015 | 05:20 PM
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bgazz's Avatar
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c240
Unhappy C 240 alarm sounding and fog lights flashing randomly

I had the water pump replaced in my C240 4matic (2004) at almost 200,000 miles. Since picking it up from the service center, the alarm system randomly sounds and sometimes, the fog lights will just be flashing with no alarm. In most cases, the smartkey will not stop these from happening and I have to go and open the car and put the key into the ignition to stop the alarm and/or fog light flashing. Yesterday when driving, I would periodically hear a chirping sound then the alarm sounded when I got out of the car. I worry my battery will go dead if the fog lights are flashing for a long period of time.

I called a local MB dealership who told me to bring it in and for $115/hour they will do a diagnostic and explore what is happening. He thought it could be checked in 1 hour but of course, no guarantee. Cost of fixing it depends on the real cause but could range from $115 for wiring issue to over $500 for siren replacement. I don't want to put a lot of money into this car given its age and mileage. I've checked the hood, trunk, windows and doors and all are closed. I opened and closed everything just to make sure.

Please help me to correct this problem! I am fine with not having an alarm if that is the easiest fix.
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Old Jan 15, 2015 | 05:27 PM
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MiataMan's Avatar
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2004 C240 4Matic
I believe Siren replacement is a DIY project. It's located just behind the right front inner fender liner. Search on this forum. I think it's been discussed before.
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Old Jan 16, 2015 | 11:27 AM
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2003 C230K & 2007 C230
As noted above. There's a battery in there that needs replacing.
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