Hi all I thought I'd post this up as a 'How to' as I had the common "Bonnet Open" error message on the dash of my 2010 X150 when the bonnet wasn't open, and to make matters worse it wont allow the car to be locked! I've searched the forum and cant find a 'how-to' on this subject, so if there is I apologise! :-)

Anyway if you've identified that it needs replacing It's a quick job to change the switch once you know where it is and they seem to be readily available on ebay costing about £25 including postage. It's also easy to bypass either on a temporary or permanent basis with a piece of wire across the plug contacts, but I'd stick a piece of tape over it to keep the water out and stop it shorting on the body etc....

The switch is located under the left hand side bonnet catch (left side as you are sitting in it) and the connector exits underneath the catch. Remove the plug from the connector and move it out of the way. If you're going to bodge it and just short out the connector then a piece of 1.5mm copper wire or a thick paper clip will fit nicely. Otherwise to remove the switch then you must remove the plastic cover which butts up against the windscreen tray and covers part of the catch. It has 4 plastic screws/plugs. Then get a marker pen and just make a mark either end of the bonnet catch so when you put it back you can see where it was! Remove the 2 x 10mm bolts and wriggle the catch out enough to prise the switch out of the bottom. (I recommend shoving a rag under the catch to block the holes so you if you drop a screw you wont lose it forever somewhere in the engine bay...)

The switch just clips in so a screwdriver gets it out quite easily.. I tried re-bending the spring that actuates the micro-switch but it seems have become 'tired' over the years and works for a while then fails so a new switch is better. Hopefully the attached photos will make it obvious what to do. Once the new switch is clipped in reverse the procedure to put it back together again. It an easy fix and this switch is probably responsible for loads of false alarms before it finally fails.


Remove this plastic cover

Remove the 2 x 10mm bolts and un-clip the cable.

wiggle the catch assembly out enough to prise the switch out from underneath

the underside of the catch assembly

The switch with 'tired' spring

How to short out the connector as a bodge to remove the error and allow for locking the car.

 

Excellent!