2007 Focus Mk2 - A Very Boring Banger

[SiC]

This is a weird one. Today my banger Focus has decided that everytime you start the engine, the boot will open. No error codes stored on any of the modules. I'm definitely not pushing the boot open button on the key either!

Google doesn't really bring back anything. Some mention about water getting in and causing it to open randomly, but this is only ever when starting up.

Not quite sure where to start on this one. Apart from removing the fuse/disconnecting the actuator so it never opens again.

Iirc the boot self locks when the engine is running to stop people opening it up at lights. I did wonder if the actuator is confusing the body computer on whether the door is open or not. Not sure why that would cause it to open. Other thought is maybe a chaffed+shorted wire where locking it causes it to open. It doesn't open when locking or unlocking the car though.

Thoughts and ideas welcome.

[paulplom]

Split pin is the boot lock master
I reckon it'll be split/damaged wires where they enter the hatch. Can you cut the rubber open for a look see?

[SiC]

It still does it when the boot is open though. But doesn't open when locking. If damaged wiring, I'd thought it would do it when locking and unlocking the car.

[SiC]

Nothing looks weird on diagnostics, apart from the boot actuator being commanded to open.

[SiC]

Interestingly I found this paperwork in the user manual. Note the circled fuses around the central locking modules. I wonder if it's had central locking issues before.

[paulplom]

Could be the earth wire chaffed? Causing it to pop open with ignition on.

[DodgeRover]

Is it the key? As the angle changes when moving to the start position something shorts inside it sending the open signal?

[SiC]

Is it the key? As the angle changes when moving to the start position something shorts inside it sending the open signal?

If you push the boot open button when the ignition is on, the boot open request from the key is ignored. Also made 100% sure I wasn't touching the button when turning the key.

[SiC]

Inside the body computer looks fine from this side. Otherside requires pulling all the fuses out.

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However there is corrosion around this connector. I don't have a pinout and my copy of autodata is broken.

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Reconnecting the body computer has fixed it. I suspect that corrosion is causing problems when the spike of starting happens.

Disconnecting and reconnecting would wipe the contacts clean which possibly why it now works fine. I'll attack it with some contact cleaner and anti static brush.

[DodgeRover]

A free fix is a good fix!