E39 external boot button not working

Another issue that I just realised may fail me the NCT - my boot button recently stopped working.

This is the one on the outside of the boot above registration plate.

These all work:

Key remote button opens it
Internal button (beside bonnet release) opens it
Physically turning key opens it

I checked the lock cyclinder position, that doesn't seem to be the problem as boot button doesn't work whether lock is in vertical or horizontal.

Am I right in thinking that if the other methods work, it's not the wiring loom?

Is this an NCT fail issue?

once he cant open the boot from outside its fail ! U will need new-another sh button

It's either the button /microswtich or loom I thought t was the button when mine went turned out to be the loom , pull the rubber sleeve back on the loom on the bootlid rhs and inspect the wiring there's a good chance at least one of the wires is damaged

Had the same problem with mine with the exact same symptoms, ended up being some frayed/broken wires in the loom in the sleeve!

Same here - With three different E39's

Loom seems to be ok, at least at the top and bottom (the bits exposed when I pull back the rubber).

Do I need to pull it all the way through to check more, or is it likely to be the switch at this stage?

http://i.imgur.com/2jVeMEf.jpg

you need to move the bootlid, and trace where the loom flexes most - I had to cut the rubber roughly half way down (where it flexes most) and found the break in some wires - tape up the rubber after you've spliced / soldered the broken wires.

You'll need a better look then that pull the sleeve out of Your way and unwind the black sticky tape Your going to have to have a good detailed inspection of the loom , make sure the batterys disconnected

Yeah, they all break where that piece of the loom bends. You'll have to uncover more of the wiring inside the rubber guide.