Hazards stay on

[rossman-abz]

Hi Guys...... Have a 2016 (66 plate) CLS 220d car and a issue has appeared. When I lock car with remote the hazards start flashing and I have to press and hold the lock button on fob for the hazards to stop flashing. After a quick look on the great GOOGLE!!!! it looks like the battery back-up from the alarm is faulty ......Would you gods of all that is Mercedes agree with google ??
Thanks in advance for all your help

 

[BlackC55]

Its very likely that the siren is faulty. Plugging it in will help diagnosing this.

 

[rossman-abz]

Is this a dealership repair or is it an easy job ??

 

[AMGeed]

Once you have diagnosed it is a faulty siren, its a pretty easy DIY job. New siren is around £100 and its just an unplug and remove the old one and refit in reverse order. Most sirens are behind the front wheel arch but I don't know exactly on your model.

 

[Petrol Pete]

As above ^^^ If the siren is behind the left front wheel as it is on earlier models it is easy to check if this is your problem. Jack the car up on that side , remove the road wheel , pop the wheel arch liner (no need to remove it fully) and unplug the alarm siren. If the fault goes away ...Bingo !
Some owners of older models just remove it altogether, not sure on your car but a faulty siren can cause all sorts of trouble , battery going flat overnight, hazard lights flashing all day etc etc. More trouble than it's worth.

Your car is only 4 years old , this part should last way longer than that, but it's easy for you to DIY check during lock down.

 

[rossman-abz]

UPDATE.

Well as I expected you guys were correct it was the siren. Got siren and connectors (which were also knackered) ..... Not very reassuring when the cars only 3.5 yrs old an d only 18k miles .....Now the alarm siren beeps once when opening and 3 times when arming the alarm. The actual car horn beeps once which it has always done.


So my query is now that the siren beeps ....has I been goosed for a long time ??

 

[AMGeed]

^ No knowing how long the old siren was inoperable.
The new sirens come pre-programmed to beep once on opening and 3 times locking. This can be disabled using Star diagnostics at an indy if you don't like it.

 

[rossman-abz]

AHHHHH. thanks very much. AMGeed.......I thought I was going slightly mad as I was sure I had never heard the beeps before. Car was only 2 months old when I bought it so the dealership must have disabled it

 

[KillerHERTZ]

Sounds like water is getting in if the connectors were gone also. - The underbody sheld damaged? generally these last for around 15 years.

 

[rossman-abz]

I thought it should be longer. The cars also had a rear parking sensor replaced. Not very good for a 3.5 yr old car with 18km miles on it. Not good advertising for Mercedes build quality

 

[KillerHERTZ]

Parking sensor replacement is common on all makes to be fair.

Id ask a garage to have a good look (with wheel off) and the arch liner as it sounds like there maybe a crack/hole allowing moisture in.

 

[rossman-abz]

Parking sensor replacement is common on all makes to be fair.

Id ask a garage to have a good look (with wheel off) and the arch liner as it sounds like there maybe a crack/hole allowing moisture in.

Unfortunately I have already got the car back.....Its a good friend who's garage that fitted siren and im sure they would have said if they seen anything that would leak.

By The way the siren was in the passenger side .....I told them the Wong side oops

 

[Wolfie1]

you can also the arm/disarm the locking beep from the dash menu