One door no longer triggers the interior lights

[8Jb9]

Hi.

My rear left door has stopped triggering the interior lights (or the MFD message about open door for that matter). All the other doors work as intended, both giving a warning and the cabin lights. I guess the switch is somewhere inside the locking mechanisms? Perhaps I could figure it out if I had the wiring diagram over the in-door connector, maybe a wire is broken?

The car is a D9 V6 pre-mux saloon.

[PeterN]

I would think there should be a switch there somewhere, hopefully someone will be along shortly to tell you where it is.

Peter

[steve_earwig]

It's in the door lock

[Doggy]

Agreed. The only drawing I could find bizarely only shows one front door & one rear door, so doesn't directly give the connector pin no.s the OP needs.

Here: https://www.petrila.net/repair/index.htm

Maybe someone else has a better drawing?

[8Jb9]

Thanks Doggy, there was a diagram there I can use - at least as a starting point.

Hopefully I won't have to mess with the water membrane to fix my issue...

[steve_earwig]

The car is a D9 V6 pre-mux saloon.

By the by, all D9s are mux, they just got loads more of it in 2001.

Sadly there's nowhere to break the wiring by the door (there is on a full-mux).

I guess that's the switch on the left. M will be the earth (I think MC%% is in the footwell) so the other wire heads off to the BSI. I'm not sure how the switching's done but I suspect it'll only earth when the door is open ('cos that's how they used to work before everyone started adding all the stupid electronics), which would follow if you can still lock the door with the central locking.

Where to start though. You can probably get to the wires where they go into the door pillar but Pug only seem to print the codes on the wires near the ends. Or pull the trim off the door post and see if you can get to them inside. I hope it's easy to spot as disturbing the membrane is a real pain.

[scoopeydiesel]

I had the same issue with a 1999 D9 and i took out the actuator on the door lock and cleaned the contacts with a nail file. It worked perfect for me after. There is a post somewhere on this.

[8Jb9]

scoopey: I'll have to look into that! Do you refer to the contacts of the connector then, or? As it happens mine is also a '99.

Thanks for the additional input, Steve.

The car is a D9 V6 pre-mux saloon.

By the by, all D9s are mux, they just got loads more of it in 2001.

Yes, I guess semi-mux or van-mux is more commonly used :-)

Sadly there's nowhere to break the wiring by the door (there is on a full-mux).

I guess that's the switch on the left. M will be the earth (I think MC%% is in the footwell) so the other wire heads off to the BSI. I'm not sure how the switching's done but I suspect it'll only earth when the door is open ('cos that's how they used to work before everyone started adding all the stupid electronics), which would follow if you can still lock the door with the central locking.

Where to start though. You can probably get to the wires where they go into the door pillar but Pug only seem to print the codes on the wires near the ends. Or pull the trim off the door post and see if you can get to them inside. I hope it's easy to spot as disturbing the membrane is a real pain.

Ah, bugger. I hoped there would be a connector right at the rubber-thingy between the door and the pillar, as on the Ms's 206. I have that door wide open with the membrane off and everything for a respray, hence knowing how much of a pain that membrane is (and I helped change a friend's checkstrap the other day on a 406 as well).

Without the connector i guess I have to get to the lock itself and check for voltage/continuity at the lock on the two pins that go to the light-switch - preferably without disconnecting the BSI on the other end.

[Doggy]

Never tried a rear door lock, but you can change the front ones without peeling back too much of the membrane.
Awkward disconnecting / reconnecting all the linkages tho.

[fattail95]

Slightly off topic, but I've never understood the differences between semi-mux and full-mux cars. Anyone care to highlight them for me please?

[scoopeydiesel]

It's the contacts on the actuator and plug in beside the lock. You will have to take off the door card, peel back the door seal and remove some of the linkages to get to it. It should be obvious enough when you see it. It's a white plastic thing rectangular in shape.On mine the contacts had corroded with moisture.

[steve_earwig]

Slightly off topic, but I've never understood the differences between semi-mux and full-mux cars. Anyone care to highlight them for me please?

We call early D9's "semi-mux" to distinguish them from the later cars but they're both muxed, just the later cars (after RPO9001, July 2001 somewhere) got a lot more of it (e.g. com2000). I reckon it's a lot clearer than just saying "early D9" and avoids assumptions by the likes of motoring journos who can't be bothered to find out (I'm looking at you "Honest" John )

[dirtydirtydiesel]

Don't worry too much about removing the membrane, just heat up the bonding putty with a hair dryer until warm and soft
You can then carefully peal it back & replace with out to much bother.
Hope this helps DDD

[8Jb9]

Don't worry too much about removing the membrane, just heat up the bonding putty with a hair dryer until warm and soft
You can then carefully peal it back & replace with out to much bother.
Hope this helps DDD

Thanks - definitely worth a try! In my most recent trip behind the membrane (3 different doors in the recent 2 months...) I cut it open, then squeezed it back together again when done - but maybe it works better if it's warmed up.

[deMarcel]

do the saloon / estate 406 have a door light on their door cars (puddle lights)? The coupe does, and when I had a blown bulb in it, it wouldn't turn on interior lights and MFD door open message either, bulb replaced, problem solved. This was on a 2000 D9 Coupe.