Alarm- 1999 C-280
 

My 1999 C-280 factory anti-theft is having premature alarmanation! Last week…for no apparent reason upon exiting my vehicle, closing the door, and setting the alarm with the remote...it immediately sounded. It continues to do this hence; I'm forced to keep my vehicle unlocked till I solve this challenge. In my efforts to correct, I discovered that the trunk lock cylinder was corroded. I removed it and had it rebuilt by a locksmith and just reinstalled…the condition still exists. I live in a cold climate, car has 85K miles and no prior alarm problems. I’m thinking sensor but would appreciate any tips on how to fix it!

On my C-230 I had alarm problems similar to yours. Mine was the front hood latch
that needed to be replaced.
This was warranty work, and the tech used a diagnostic toll to find the problem. The Haynes manual suggest a dealer and states the diagnostic tool will quickly find the problem.

Right. When the alarm is activated (other than Panic Alarm button on the key) it will set a code, so the tech can read out trouble codes for ATA and be pretty sure where the problem is.
Gilly
ps I'm voting for the right front door switch, and can probably be fixed by adjusting the door tighter.

Right front door switch...why?
 

Thought I had the problem whooped...still could be a faulty hood switch. But...why for do you say the right front door switch??

The Mercedes diagnostic tool can trouble shoot your problem real easy.

Just because I've seen alot of right front door switches setting off alarms, could be something else, like the hood switch;) .
Gilly