I’ve mentioned on and off that the 330d’s boot glass has been misbehaving. The first symptom was that the button under the rear wiper stopped working. I could live with that. However, then the lid starting popping open at random times of its own accord. Rather irritating when you’re driving along; extremely worrying when it does so when parked at night – boot lights alerting any would-be criminal that it’s open.

A couple of weeks back I dismantled the assembly and cleaned it up. This brought the switch back to life, and I thought it had stopped the boot from opening of its own accord, but recently it started playing up again. I’ve therefore invested in a replacement unit, and have installed it today. Here follows a step by step procedure for anyone else who is suffering the same.

Parts:

B61.31.9.218.995 – key button
B61.31.9.218.995 – gasket

Before any discount but including VAT these cost £30. The ‘key button’ was in stock but the gasket wasn’t, so I had to return to collect that later. Annoyingly, when I came to do this job I discovered the ‘key button’ came with a new gasket so that part wasn’t required at all. I’m not certain if this is supposed to be the case or not, but certainly worth checking, and if you don’t need to order the gasket separately, it’ll be more like a £25 job.

So, the procedure. Open the boot glass. Remove the two plastic covers, and unleash a 10mm socket to free the plastic housing.

Undo the newly visible 10mm nut.

Next lower the glass lid and attack the outside. The rear wiper’s plastic hinge cover should come off with a bit of persuasion to reveal a 13mm nut. Whip that off.

That will allow you to remove the wiper arm – you may need a spot of leverage with a flat head screwdriver to pop it off the splines.

Then get a 24mm socket on the exposed nut. Once that’s off, the switch needs disconnecting from the car on the inside, and all parts can be removed. This should leave you with a pile of goodies that looks something like this:

Clean everything up “good and proper”.

Reassemble with new switch and gasket.

So far everything it good: the switch works and the lid has remained shut. Only time will tell how permanent this fix is!