Bonnet open warning

[Scouser51]

Hi everyone, is there a knack for closing the bonnet on a 2018 E Class? Every time I occasionally open mine and close it, on the next use after about a mile the bonnet open warning alarm sounds.

 

[markjay]

There's a sensor on one of the bonnet locks at the front, check that it's not loose, or replace it if need be.

 

[markjay]

 

[Scouser51]

There's a sensor on one side of the bonnet locks at the front, check that irs not loose and that it's moving freely, or replace it if need be.

Many thanks very useful response.

 

[SpikyMikey]

If it's anything like my C Class you have to drop the bonnet from about 8-10 inches up rather than push it shut, otherwise one or other of the locks doesn't engage properly and you get the dash warning.
Must be a German thing because my Beemer is the same.

 

[rayaans]

Mine happened once. It's annoying as hell as just keeps beeping.

Turned out the latch was not secure on one side so needed opening and then closing.

Sometimes the rubber stoppers need twisting to make sure they're not preventing it closing fully

 

[AMGeed]

As above, give the bonnet a good slam and the warning doesn't appear.

 

[Scouser51]

Thanks everyone, very informative advice

 

[sceh]

There are, like all mercedes, TWO bonnet locks and both have a switch inside. One is 'normally open' and the other 'normally closed'. From the front, the right hand side one is OPEN when the bonnet is shut and the left hand side is CLOSED when the bonnet is shut.
So, buy new switches from Alibaba but don't buy new catches since they are OK. To change the switches, unbolt the catch, pull it out a bit, unclip the old switch and remove and clip in the new one.
In the interim and if you can't get switches, UNPLUG the right hand side to fool it the bonnet is shut and short out the left hand side to fool it the bonnet is shut.
Some people say you can bend the springs inside the switches but it never works for long so it is not worth the trouble.
Problem solved