Good evening fellow A6 owners 

I am looking for some help,I have a 2010 model and everything is excellent apart from recently I've been having issues with the alarm and the bonnet open notification,I have changed the latch (with sensor) and still it's persisted so I ended up unplugging the sensor near the headlight and it went off for a few days but now it is back...

It seems like no matter what I try I keep getting this intermittent fault and the alarm goes off in the night and day,I'm starting to wonder if there is another sensor on the bonnet although I can't see one anywhere? obviously there aren't any fault codes but another thing is,when the "bonnet open" notification is on the dash,you can't use the wipers so I may become a big issue in the winter.....can anyone help??

The wipers will not work if the car senses the bonnet is open. It's an interlock to prevent damage to wipers/bonnet.

Have you checked the earth connection of the new switch? Is there damage or corrosion in the switch connector?

2 minutes ago, cliffcoggin said:

The wipers will not work if the car senses the bonnet is open. It's an interlock to prevent damage to wipers/bonnet.

Have you checked the earth connection of the new switch? Is there damage or corrosion in the switch connector?

Everything looks fine,even the wiring from it to the connector,sounds crazy but would a poor battery cause an issue like this? another thing is once I start to drive it goes off but sometimes it will flash up a couple of times whilst driving then just go away.

10 minutes ago, steve_dc said:

,sounds crazy but would a poor battery cause an issue like this? 

Very possibly. A dying battery can cause many unrelated electrical faults. If you have any doubts about the battery or it is more than five years old it would be well to get it tested on professional equipment.

5 hours ago, steve_dc said:

Good evening fellow A6 owners 

I am looking for some help,I have a 2010 model and everything is excellent apart from recently I've been having issues with the alarm and the bonnet open notification,I have changed the latch (with sensor) and still it's persisted so I ended up unplugging the sensor near the headlight and it went off for a few days but now it is back...

It seems like no matter what I try I keep getting this intermittent fault and the alarm goes off in the night and day,I'm starting to wonder if there is another sensor on the bonnet although I can't see one anywhere? obviously there aren't any fault codes but another thing is,when the "bonnet open" notification is on the dash,you can't use the wipers so I may become a big issue in the winter.....can anyone help??

Hi if you get the battery properly checked under load and it proves to be ok the next port of call would be the alarm module as these are often prone to failure due to the fact they site them in stupid places and the connectors corrode and cause shorts in the unit, I dont know where yours is fitted but it might well be worth researching it and check the connector plug.

Steve.

58 minutes ago, cliffcoggin said:

Very possibly. A dying battery can cause many unrelated electrical faults. If you have any doubts about the battery or it is more than five years old it would be well to get it tested on professional equipment.

It's 14 years old lol

11 minutes ago, steve_dc said:

It's 14 years old lol

BINGO!!!!

Always eliminate battery inefficiency as being the cause/aggravator of any electrical issue before moving on to more complex possibilities. 

So guys,I just got a new battery on,and early days still but so far no alarm going off and no warning on the dash....but I will update if it does come back

Thanks Stephen, 

Can we take it you didn’t bother to get your old battery tested? What brand of new battery did you buy, and did  you have it coded to the car. 
Re. reporting if you have a reoccurrence of the issue, could you do us a kindness and let us know at the end of the month whether the problem remains solved or not? 
Failure to respond would leave the thread open, and other members unsure of whether it was the solution or not, and we are striving hard to avoid that.

Many thanks, Gareth. 

Hi,I did get the old one tested and it was great so they recommended that I put a new one on seeing as it was old and winter is coming so I opted for the Varta AGM,but today the issue is still carrying on,like I have said I tried a couple of new genuine latches but sent them back when they didn't resolve the issue,I have ended pulling my hair out and not locking it when I'm in meetings etc as it's now beyond a joke,I'm.mot sure where to go from here.

Sorry about the additional questions Stephen, but did the battery suppliers and fitters:- 

Also check the alternator output?

Code the new battery to the car? 
Regards,

Gareth. 
p.s. Questions asked in relation to the car behaving properly for some days after. 

1 hour ago, steve_dc said:

Hi,I did get the old one tested and it was great so they recommended that I put a new one on seeing as it was old and winter is coming so I opted for the Varta AGM,but today the issue is still carrying on,like I have said I tried a couple of new genuine latches but sent them back when they didn't resolve the issue,I have ended pulling my hair out and not locking it when I'm in meetings etc as it's now beyond a joke,I'm.mot sure where to go from here.

Hi as suggested its probably the alarm module, not sure where it is on your car but on the C7s its under the front Scuttle where it can get nice and damp and the connections can corrode done a couple of them and C7 modules are expensive circa £500 but I have had some success with second hand units from my local VAG breakers £70.00.

Steve.