triangle12

I have an 05 C55 with 130k miles. Started the car this afternoon and roughly 30 seconds after starting (while idling) the car makes a loud alarm type screech. It lasted a couple seconds then started up with the noise again. It did this 3 times while still in park. At first I thought it was a car alarm going off on the car next to me. Started to drive home and same alarm type noise happened again (lasting a couple seconds). Once home, I have learned that it now makes a long chirp/alarm type noise every time I lock the car using key fob. Noise is coming from front passenger area under hood, near battery & fender well (best I can tell). Any idea what is going on?? THANKS!

Rahulio1975280C

It sounds like your alarm siren is failing. When this happened to me, I replaced the unit and all the issues went away.

Mercedes-Benz Alarm Siren (If replacing old siren with part number 1718202526, you will need 8mm stainless steel nut to install 2198203226)

Very simple DIY repair.

triangle12

Thank you so much for the help! If I disconnect it until the part arrives, it won't cause any problems with message center/engine light etc?? It's my daily driver.

Rahulio1975280C

I don't think it will cause issues, but I had to replace mine in the garage at 4AM on a 32 degree F morning. I already had the parts on hand, and wanted to wait until the weekend, but then the alarm went berserk and nothing I tried would make it stop, so I just replaced it right there.

If you were to disconnect it, make sure you wrap that connector for the alarm siren. Make it water tight, you don't want any moisture to get into that connector.

You need to lift the front axle, remove the front right wheel, remove the fender liner, and then you will see the alarm siren. Common sense will do the rest.