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Car Alarm/Bonnet Sensor issue


jonny_sniper93
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Hey all, 

I have a 65 plate ZS and I constantly drive around with the 'bonnet open' warning (even though it is closed). Furthermore, the alarm keeps going off on the car so I don't doubt that the two are linked. The car is booked into Ford (but not for 2 weeks) so I just need advice on a short term fix:

1. Is there any way to disable the alarm or the bonnet sensor? I unplugged two plugs that go to the bonnet latch, but that didn't help. I assume it left me with a broken circuit and I don't really want to be cutting and connecting wires.

2. Is there any way to lock the car without alarming it? I thought that pressing the fob once just locked it and twice alarmed but this doesn't seem to be the case.

3. If I leave the car UNLOCKED, will it auto lock itself once I walk away? Whenever the alarm goes off and I unlock it, the alarm seems to go off again a minute later. I don't have a problem leaving the car unlocked if I have to. Currently I am leaving the door ajar. 

It was intermittent but yesterday I tried giving the bonnet latch/sensor a wipe because it seemed very dusty but I seem to have made it much worse/sensitive. As you can imagine it is embarrassing at work/home. Thank you in advance for any help.  

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My dad had the same issue of the alarm going off, Ford replaced the bonnet latch under warranty.

His was worse when it was hot, or he'd just got back from work and the engine was hot.

I believe you can disconnect the connector then use something like a paperclip to bridge the pins and make the car think the bonnet is shut.

If you leave the car unlocked, it won't auto lock, it only ever locks if you unlock it then don't open a door. I wouldn't recommend leaving your car unlocked though.

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41 minutes ago, alexp999 said:

My dad had the same issue of the alarm going off, Ford replaced the bonnet latch under warranty.

His was worse when it was hot, or he'd just got back from work and the engine was hot.

I believe you can disconnect the connector then use something like a paperclip to bridge the pins and make the car think the bonnet is shut.

If you leave the car unlocked, it won't auto lock, it only ever locks if you unlock it then don't open a door. I wouldn't recommend leaving your car unlocked though.

Thanks for the reply, I'll have a play around with it tonight and see if that'll work. And, yeah, mine seems to be worse when hot. Thanks again.

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Could be mistaken, but I've always thought second lock was imobiliser.

Could find a wiring diagram and pop the fuse out, but I'm sure you'll take a whole load of other stuff out with it. However if you're going to the trouble of doing that, it's better off to just bridge the connectors, unless there's a problem with the wiring harness of course.

 

 

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4 hours ago, Luke4efc said:

Could be mistaken, but I've always thought second lock was imobiliser.

Could find a wiring diagram and pop the fuse out, but I'm sure you'll take a whole load of other stuff out with it. However if you're going to the trouble of doing that, it's better off to just bridge the connectors, unless there's a problem with the wiring harness of course.

 

 

I believe the book says the second press prevents the doors from being opened from the inside, iirc. 

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  • 2 years later...

Hi I have a similar problem with a Ford Fiesta 1.4 58 reg.  About 6 months ago alarm started going off 6/7 times a day/night.  The Ford Dealer diagnosed it was a faulty boot catch and replaced this.  Alarm still kept going off so Ford Dealer had car for a week.  They couldn't make alarm go off and it didn't keep going off so they said the problem was solved.  As soon as car came home alarm kept going off so Ford Dealer had it back and disabled horn.  So we just had to put up with lights flashing and as car is only used occasionally I had to remember to take it for a run once a week.  But this week car has been used every day and the boot and rear passenger door on drivers side have locked and we can't get them unlocked and lights keep flashing almost continuously.  Apart from leaving car unlocked has anybody got any suggestions as to how they fixed this problem and any ideas how to open the boot and door?  Need to do something otherwise battery is going to run down and car is going to lock and not let us in. 😁

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  • 1 year later...
On 8/8/2019 at 5:53 PM, janebrill38 said:

Hi I have a similar problem with a Ford Fiesta 1.4 58 reg.  About 6 months ago alarm started going off 6/7 times a day/night.  The Ford Dealer diagnosed it was a faulty boot catch and replaced this.  Alarm still kept going off so Ford Dealer had car for a week.  They couldn't make alarm go off and it didn't keep going off so they said the problem was solved.  As soon as car came home alarm kept going off so Ford Dealer had it back and disabled horn.  So we just had to put up with lights flashing and as car is only used occasionally I had to remember to take it for a run once a week.  But this week car has been used every day and the boot and rear passenger door on drivers side have locked and we can't get them unlocked and lights keep flashing almost continuously.  Apart from leaving car unlocked has anybody got any suggestions as to how they fixed this problem and any ideas how to open the boot and door?  Need to do something otherwise battery is going to run down and car is going to lock and not let us in. 😁

Did you ever find a fix?

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  • 2 years later...

I’ve had the same problem with mine for the last couple of days I just unplugged it and bridged the sensor with a bit of cable for a short term fix 

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42 minutes ago, dawn tobin said:

when bridging do you have to disconnect the battery please ?

No it shouldn't be necessary if just shorting the two pins on the bonnet latch sensor. There is no meaningful voltage, it is just sensing whether the circuit is closed (bonnet shut) or open.

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