Mk7 2010 Boot Opening On Its Own

[K-Singh]

The car recently developed the problem where the bootlid opens on its own. It dosent do it when the cars locked only when the locks are open. I understand other people on the forum have had the same issue. Is it the boot latch at fault or the boot opening switch?

[igglepiggle]

Common fault on the Fiesta, its either the boot locking mechanism or the boot opening latch.

Ford replaced my boot opening latch on my 2013 Fiesta last week as every time you started the car the boot opened also I could only open the boot using the remote.

[AdamC11]

Hi K - Singh,

I had mine done the other week and it was the boot locking mechanism. Ford charged £58 for the part and labour.

Hope this helps?

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[K-Singh]

Thanks for the replies Ive been on the phone with ford and they were sure its the switch so ive ordered that for tommorow if not i l just return it and get the mechanism

[CathodeRay]

Anyway I was still intrigued...why does the damn switch keep decking the BCM line?
Well I unscrewed the switch six screws or thereabouts and desoldered the little switch inside from  the pcb track.
I then opened the switch up and inside the construction is two rings of copper separated by a spring and contact bridge
One of the rings had come loose through oxidation and was intermittently shorting across to the ground line depending on the orientation of the switch.
Ahhh random is how you slam the boot or orientate the switch.

Anyway mystery over.....you can fix this easily if the symptoms are random boot opens when doors are in unlocked state but ok when doors locked.

Follow the description for panel removal to replace the switch in the bootlid given by k-singh above. If you are a demon with a screwdriver you might be able to prise it out but risk damage to the bodywork perhaps. Frankly it takes less than 20 mins to gain access and remove it with the right tools. Watch the clips.
The BCM ignores any commands to open the boot when the doors are in a locked state UNLESS you tell it via the remote key fob dedicated button.
I should be careful with the use of the term "command"as it implies some form of intelligence. The BCM feeds the switch 12v via a resistor and the switch in the boot just decks it to the BCM ground signalling  the processor in the BCM to send a pulse to the boot lock mechanism...its a 12v DC for about 0.5 secs maybe a bit more
New switch on eBay under a tenner. Game over.

Save yourself a boot locking mechanism...it wont be that unless it refuses to unlock...that's something different.

[tekopikin]

Hello @CathodeRay

I know it's a long way from 2010 when you posted this response, but I'll try regardless. I recently acquired a 2010 Ford Titanium which is exhibiting a similar fault, the boot will only open by using the button on the keyfob.

As a previous Mk5 owner I was not familiar with the intricacies of the Mk7 when I was purchasing the vehicle and was unaware this was a fault till I spotted another driver opening their boot manually from the outside 🤦‍♂️

On the Mk5 I was able to pop the boot open by pushing a button on the dash, is this the same for a Mk7? Is there such a button or is it completely manual or using the keyfob? 

Thank you. 

[TomsFocus]

1 hour ago, tekopikin said:

On the Mk5 I was able to pop the boot open by pushing a button on the dash, is this the same for a Mk7? Is there such a button or is it completely manual or using the keyfob? 

There is no dash button for Mk7.  Just a button under the Ford badge on the tailgate.  These buttons break fairly regularly, so chances are you just need a new one.

Here is a link to the genuine part.  You may choose a cheaper aftermarket part instead.  Genuine Ford Rear Boot Tailgate Lock Switch 1857333 | eBay

[tekopikin]

Thank you so much @TomsFocus
Much appreciated 😊