E39 - K&N Filter

Late afternoon, 3:30 pm, I decided to have a look under the O/S wing where the windscreen washer bottle is situated, to check the wiring and to also have a look at the back brake dust plate. First jack up the vehicle and take the wheel off, now for the water bottle. The under wing 'boot, skirting,' call it what you will, has around 7 screw bolt heads and around 4 plastic push studs, only the lower half of the skirting needs to be exposed. Note: Be careful with the skirting on the edge of the wing and the plastic push studs, as these can be damaged easily so care should be observed when taking them out or cosmetic repair and/or replacement will be needed.

I checked the wires and insulated them, nothing really unusual there except the one wire on the left, (as seen in the image) was connected to the offside wing light indicator, the functionality, wiring was checked and was ok. This has now got me thinking after insulating the wiring behind the glovebox, the head unit and now the inner offside wing the problem with the battery drain could be just down to the wiring going to the steering column and a possible faulty stalk or ignition switch.... (Note: I have noticed the wiring to the windscreen washer pump cannot be accessed from the O/S filter box inside the engine compartment as it does not go through the bulkhead grommet at this point and I can only conclude this wiring feeds through to the N/S Fuse cluster within the engine compartment).

At this point in the job, it can be a good idea to just check the water bottle for leaks, clear out debris such as leaves and dirt (behind the pump), check for wear and tear on the inlet/outlet hoses, washer grommets and all important while you have access, check the function of your washer pump, condition of breakpipes, a good general look-a-round before moving on to reassembling the inner arch skirting. To safeguard any possibilities of water shorting out the water pump, I also decided to insulate all the electrical plugs connnecting to the bottle.

Refitting the Arch skirting, this job in itself can be fiddly, especially when aligning up the bolt holes, so be prepared to allow a few extra minutes for this.With bolts put in place and the odd plastic stud repaired or replaced.

Don't forget to top-up the bottle if you have
allowed water to escape during your test.

Replace your wheel, tighten bolts, lower the jack, re-tighten wheel bolts. This job is done.