Bonnet open warning .

littlewimp

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Whilst travelling home on Sunday i had the bonnet open warning come up on the display, it was coming on and off intermittently then went off and stayed off for the remaining 30 miles, anyway last night i was woken by the alarm system on the car so am guessing this could be connected via a faulty bonnet switch? im sure i can find it but wandered if its something that fixable or would i require a new switch which is whats recommended when a similar fault occurs on the BMW .
 

AJD

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I've had this happen to me. I just opened the bonnet and closed again and the problem did-appeared :)
 
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littlewimp

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I've had this happen to me. I just opened the bonnet and closed again and the problem did-appeared :)[/QUOTE

i shall give that a go , tbh its the first time i've had a problem since ive owned it.
 

John Laidlaw

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Haven’t had it valeted recently have you?
 

00slk

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These symptoms usually surface when ones speed creeps above the legal limit ;)
Not that I have ever had this unusual event happen to me, but I have been informed that a good slam shut of the bonnet will relieve said symptom :D If not then faulty switch could be the culprit. :)
 
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littlewimp

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No not lately John, but i have had no option to leave it outside for several weeks.
 

John Laidlaw

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Only asked as my SL500 bonnet did the same after my detailer failed to close it properly after doing the engine shuts- drove off quickly and warning on!
 

Submariner1

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Whilst travelling home on Sunday i had the bonnet open warning come up on the display, it was coming on and off intermittently then went off and stayed off for the remaining 30 miles, anyway last night i was woken by the alarm system on the car so am guessing this could be connected via a faulty bonnet switch? im sure i can find it but wandered if its something that fixable or would i require a new switch which is whats recommended when a similar fault occurs on the BMW .

I had to undo these 2 bolts to take out the bonnet catch lock as the surround had cracked.
In doing so one finds a wire with a tiny microswitch that plugs in.
I would check that before opening and closing the bonnet too much.
6AECF979-52AB-4188-9B72-074E75CB332A.jpeg
4 minute job to undo those and check the micro switch. I sprayed wd40 on it to clean it. Sprayed contact cleaner in it, and then some Silicone grease on the moving pin.

If the switch came loose the U bracket would smash it, and on mine its part of the loom dissapearing off under the sidewall covers. Hence the “maintenance” clean up
7D6608E0-6170-4590-AB96-366CB76874C8.jpeg
 
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littlewimp

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Thanks for the replies, i will take a look as soon as i get a chance.
 
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littlewimp

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These symptoms usually surface when ones speed creeps above the legal limit ;)
Not that I have ever had this unusual event happen to me, but I have been informed that a good slam shut of the bonnet will relieve said symptom :D If not then faulty switch could be the culprit. :)

I believe that creeping slightly above the Speed limit could be a factor.
 
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littlewimp

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Gosh, I could not possibly comment Sir :D

Checked the switch and it all seemed Good for several weeks however became very annoying after a trip to essex on the weekend, must of had warning displayed 100 times when accelerating up to Max speed limit. Im hoping to have the new switch delivered so i can fit it over the weekend and the problem go away !
 
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littlewimp

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Ive got the new micro switch for the Bonnet and have had a quick look at fitting it, i'm guessing that the catch has to be removed from the slam panel, but before i take the complete front off the Car can someone give me a procedure. the switch looks to be enclosed in a plastic enclosure from the underside and the release cable seems quite tight which wont allow enough movement to remove the catch also i have the wires on the switch to contend with.
Thanks Neil
 

Ardingly

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Whilst travelling home on Sunday i had the bonnet open warning come up on the display, it was coming on and off intermittently then went off and stayed off for the remaining 30 miles, anyway last night i was woken by the alarm system on the car so am guessing this could be connected via a faulty bonnet switch? im sure i can find it but wandered if its something that fixable or would i require a new switch which is whats recommended when a similar fault occurs on the BMW .
 

Ardingly

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Hi, I had my car given its annual MOT test on Thursday and it came back with the bonnet open warning flashing and beeping. Oddly a year ago at its MOT the same thing happened and both sensors needed replacing. I may have opened the bonnet to add windscreen fluid since then but possibly not opened it at all during the year. Difficult to believe that the sensors have failed again. It will go in again for a diagnostic check but has anyone experienced this before?
Also, by the by, when this is happening the beeper sounds continuously with a red display all the time the car is moving and the audio is muted. Stopping at a T-junction or traffic lights the beeping stops, the audio comes back to normal volume and if it's raining the windscreen wipers stop! Moving off it all reverts again. Why do the wipers need to stop??????????
 

mioba

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did you change with genuine parts.
 

Ardingly

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did you change with genuine parts.

Thanks. Yes as far as I know. I used my usual reputable garage but not a Mercedes dealership. They normally ask if they want to use non original parts as the originals are often far more expensive.
 

EXMERCTECH

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These symptoms usually surface when ones speed creeps above the legal limit ;)
Not that I have ever had this unusual event happen to me, but I have been informed that a good slam shut of the bonnet will relieve said symptom :D If not then faulty switch could be the culprit. :)

Usually followed by flashing blue lights in the rear view mirror.
 


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