Bonnet open warning

[thebook]

Morning all,

I topped up my screen wash at the weekend and when I started the car this morning, the bonnet open warning light was on (centre screen red with an image of an open bonnet).

I got out and checked but it was definitely closed. I released the bonnet and slammed it shut but this made no difference. I then drove to work with constant alert bongs (which was painful). Any tips on how I rectify? I plan to spray all hinges/locks with WD40...

 

[Dec]

What year is the car?

Try locking the car with the remote and see if the hazards flash 2 times or 3 times.


Dec

 

[Riva811]

Morning all,

I topped up my screen wash at the weekend and when I started the car this morning, the bonnet open warning light was on (centre screen red with an image of an open bonnet).

I got out and checked but it was definitely closed. I released the bonnet and slammed it shut but this made no difference. I then drove to work with constant alert bongs (which was painful). Any tips on how I rectify? I plan to spray all hinges/locks with WD40...

Same thing happened to me because I tried to be gentle. I opened the hood again and let it fall from 30cm and it worked.

Sent from my G8141 using Tapatalk

 

[thebook]

Thanks for the replies. The car is a 2011 A207 (E Class Cab). I will check how many times the lights flash when locking. The internal catches seem very

 

[ioweddie]

Just re open it and drop it closed with a little push

 

[grober]

Check the bonnet catches- at least one of them has a switch incorporated in it.

similar to this

 

[thebook]

Thanks everyone for your swift replies. I can confirm a liberal squirt of WD40 on the areas highlighted in the above diagram seems to have done the trick! All good in my world now, no more annoying bongs...

 

[190]

That's odd as I had the same problem recently. When I removed the contact sensor shown in the photo above there was a tiny bellows seal on the micro switch operating pin which looked like it would prevent WD40 from getting inside the switch. What I did instead to ensure the switch was being actuated properly was to bend the leaf spring slightly (visible just to the right of the epoxy resin) that transfers the movement of the bonnet catch to the micro switch pin and that cured the problem. I also greased the mechanism while I was in there.

 

[thebook]

There catches were so tight there was no spring in them. I guess the WD just provided sufficent lube to loosen them up. They now spring and all is good.

 

[grober]

If the problem comes back you could try a light persistance type spray grease such as a lithium /teflon containing one as WD may get washed away. Halfords stock a range of these or your MB dealer can advise.

 

[topdown]

Make sure the release handle is pushed back after opening.

 

[brianpaul]

This problem is an easy fix on my w212 e class all you need to do is lengthen the bonnet catch on each side by adjusting the 13mm nut so the catch gets slightly longer and this will push the sensor down more when the bonnet shuts.