The wife's CMax started playing up the other day. I knew for a while that she couldn't open the boot using the switch, only the remote button could unlock the boot. No big deal, so we left it.
However, a couple of days ago, the boot started opening at random times, mainly when the car was started. It quickly progressed to opening whilst driving or sticking it into reverse.
I had a look on here and the internet. It looked like I might have to shell out a few quid for a new switch. I read that recently someone had used a small button switch from a mouse, so I thought I'd have a go at that before giving my hard earned cash to the people who designed the car badly in the first place!!
Hex bit for screws in grab handles
10mm spanner (ratchet spanner preferred)
Soldering iron and solder
An old computer mouse
This is what I did;
I removed the 2 screws in the grab handles at the bottom of the bootlid cowl. Then I gently prised the cowl off the bootlid. This was surprisingly easy to do and none of the clips or plastic broke.
I then loosened the 4 nuts that hold the outer plastic trim using the 10mm spanner (where the boot switch is located) onto the boot. I prised this away from the bootlid and pushed in the grey plastic clips on the side of the switch mechanism which released it. I then unplugged the switch from the loom and removed it from the car (along with the grommet). (You can see I had 3 switches lined up to see which fitted best, 2 were from the mouse and one was from an old led bike light)
I peeled back the rubber 'gaitor' from the switch and found the same white powdery stuff that others have found, which meant that water ingress was probably to blame. I gave this a good clean and had a play with the switch to see if it still worked. The multimeter told me it was intermittently faulty.
I removed the original seal where the wires join the switch and pushed the switch out from the bottom of the plastic trim.
I found an old mouse and butchered it. I got out my old soldering iron and removed a couple of hopeful switches, stabbing myself in the palm in the process. I am a rubbish solderer, so if I can manage it, everybody else can!!
I cleaned up the plastic trim and dried it thoroughly.
I then de-soldered the original switch. I fed the wires back through the little gap and soldered the new switch on. Took me half an hour because I'm terrible at it. A couple of burns later and it was done.
I had some strong superglue lying round, so I used that to fix the new switch in place, making sure it lined up with the button in the trim.
I didn't have any clear silicon sealant so some white anti-mould shower sealant had to do the job. I plugged up the hole by the wires thoroughly with the sealant and made sure it was neat inside the trim.
Next up was putting the rubber trim back in place. Some careful application of the sealant later, and the whole switch was watertight (hopefully).
I put it all back together and for the first time in a couple of years the boot opens using the switch. The random problem of it opening seems to have stopped as well.
It's early days but looks promising. Only took an hour or so and didn't cost me a penny either!!
This seems to be a common problem with CMAX's and Focus' between 04 and 07. I've put this in a couple of places as well to help as many people with this problem as possible.