2004 mercedes c240 alarm sounds for no apparent reason

My best guess is that the remote is going bad or the receiver sensor in your car is getting goofy. But my money is on the remote itself. It's been used and banged around for 10 years and the inner workings just plain wear out. Just found out the average life span of a tv/cable DVR box is 2-3 years.

pressing lock button should activate alarm sound. system, when you press unlock button that deactivates alarm sound.i you dont hear alarm sound problem is in the ecm.

UN HOOK THE ALARM WIRE THAT GOES TO ALTERNATOR

if its an aftermarket alarm, which im sure it is, find the brain to the aftermarket alarm and unhook it. trace the brain back from the car alarm siren hardware. it shoud b mounted somewhere under the hood. theres not a lot of available space in the engine compartment. so you should easily find the siren hardware. trace the wiring back to the brain and disconnect it. it cant be factory alarm. factory alarm only goes off when u dont use keyless remote or key to unlock a locked door or trunk. factory alarm blows horn and blinks parking lights

My Mercedes C-Class 1996 won't start up, the alarm is confused it thinks it's locked, every time i unlock it, the red light( locked) and green light(unlocked) flash at the same time constantly, if I open the car and try turn on the engine, the alarm starts blaring, I've turned it on before and drove it around but when i came to park it up it did not turn on again because of that problem.( The car hasn't been touched or used for a year before i got it going again)

sounds like a bad door trunk or hood switch.

Hi,

Bluetooth compatability is available on Merc vehicles which were originally wired with factory handset (Motorola), iPod adaptor cable & wireless Multi-Handset Interface (MHI). Models from 2007 onwards also had an updated interface.

If your vehicle has the MHI, then it would be a simple case of activating the the MHI device to search for your iphone device.

If you are unsure if you have the MHI adaptor, then contact your local Mercedes Parts Dept. for further advice.

Cheers,

sounds like a low tire pressure light. check tires and set to factory specs as indicated on the drivers door pillar.then drive at about 40 mph. the light should go out.

it could just be a fulty sensor or there is low oil presher,, maybe a blocked oil filter but have it checked out fast,,,

sounds like the hood alarm switch is not making proper contact with the hood, the alarm will not set properly, check the hood alignment