Any 406 electrical experts? HELP REQUIRED *

[DaveyRapier]

Hi all. As the story goes have myself a D9 HDI Saloon, owned it from june have had many problems with it but all fixed now bar one. The bloody central locking, I lock the car it unlocks straight away. After much head scratching and changing things to no avail I noticed that my interior light (set to come on when the door opens) illuminates when I open all the doors except the drivers. When I open my drivers door it just stays off. I believe this is my problem that the car is unlocking itself again because the light is not operational. So I went about changing the door latch with the microswitch to fix it, ended up changing the whole locking module including the latch to a fully tested and woking module off ebay. Nothing changed it still doesn't light up.

Anyone ever come across this before or shed any light? What else could be doing this. The car has been hit before on the drivers side so this most likely has something to do with the problem. Any help at all appreciated!

[Doggy]

It could well be broken wire(s) in the bit of loom that flexes each time the door opens / closes.

I've never touched one on a 406, but have sorted electric window & c/locking problems on other cars that were down to this. Hopefully someone with more relevant know-how / experience can explain further?

[steve_earwig]

The car has been hit before on the drivers side so this most likely has something to do with the problem.

I thought this would be the important bit - the cable has probably been squashed. Failing that the switches use earth signalling, which won't work if there's no earth - once more it's in the driver's footwell

[DaveyRapier]

I have changed the entire drivers door loom there are definitely no broken or squashed wires.

The earth point in the drivers footwell, is there an earth point for each door with regards to the interior light? Just wondering with the light still operating for my other 3 doors? I will take a look anyway and see what's happening in there. Thanks for the replies chaps.

[steve_earwig]

I have changed the entire drivers door loom there are definitely no broken or squashed wires.

That eliminates that idea then.

The earth point in the drivers footwell, is there an earth point for each door with regards to the interior light?

Sort of - the doors do seem to have separate earths (the diagram I have only does the doors on the lhs but I can see the earth for the rh front door in the diagram) but it just uses it to send signals to the BSI with regard to the state of the door lock and if the door is open. The BSI turns on the light.

Btw does the car have lights on the door cards? They share the same earths...

While I'm thinking about it, I'm assuming the car doesn't have deadlocks - it's possibly irrelevant because the diagram just shows another switch in the lock but it would be useful to know if it has them and if they work or not.

[steve_earwig]

Just to clear it out of my head: it's probably the first thing you looked at but check the door loom connector is pushed home and not full of corrosion... (looks like it's 16 way and white)

[DaveyRapier]

No lights on the doorcards. What exactly are deadlocks? Pretty sure there is nothing like that on the car anyway. Any chance you could host this picture here just so I can get a look at it before I go searching in the footwell?

Door loom connector is definitely home and I took both plugs apart and cleaned the connector pins when I was fitting the new loom. The central locking problem was the same before and after the loom change I had to do it to get my electric windows and mirrors to work. (bodge repair work by previous owner don't ask)

[steve_earwig]

If you don't know what deadlocks are then your probably don't have them

Which picture?
Wiring:

I'm not 100% on what's what, although it looks like the middle switch is the deadlock, which yours will lack along with the 3rd wire to the motor. I think.

Earth (and the lesson is: Next time look at the lock diagrams, not the lighting ones ):


I reckon you should head straight for the loom connector and check it for an earth, then check through it towards the door for continuity with the door open & shut.

[k_f]

I had a thought which might be relevant although I've not seen this problem before. When I try to lock my car the locking operates and then immediately unlocks itself if a door is open. Maybe your car thinks a door is open ? My GTX uses the multi-function display to show if a door etc is open. Does yours have this ? Maybe not as you would spot it straight away or maybe my point is irrelevant.

[DaveyRapier]

steve_earwig You are a gentleman thanks for the image will take a look the next chance I get an come back here with an update on my issue.

k_f Yeah my car has the display to show if a door open or closed nothing showing on it unless my doors are open, I think my issue with the light not illuminating is the car doesn't see the door opening at all.

[DaveyRapier]

* THREAD REVIVAL

Still no joy with this. I have put 3 different central locking modules in the car now to no avail. Each one definitely operational but I was told there are 2 different types and if the wrong one was fitted it wouldn't work. Anyway I definitely have the right one in now from a D9 rapier 90 bhp.

The interior light still does not come on when the door is open, nor does the display panel show a car with the drivers door open and thirdly the door open light on the clocks does not illuminate. Strangely I have realised when I put my key in the door and try and lock it from the outside the key does not turn at all?? Can't see anything wrong with the way I have connected the wire pull from the locking module so have no idea why this is! Also when I push the button on the inside door handle to lock the doors it only locks the drivers door and no others? Yet on the other doors when the button is pushed all the doors lock then unlock straight away.

I have checked the earth point in the drivers footwell and it is fine and not corroded. I have not checked the loom for continuity of earth because I have no multimeter and also don't know how to if I did

Can someone please HELP ME with this. I really have no idea what to do now and leaving the car open all the time is just not practical. I even left the car into an AutoSpark who turned out to be completely useless and charged me £40 for not doing ANYTHING with it! Took the doorcard off looked at it, hadn't a clue and screwed it back on.

[steve_earwig]

Can you not lock the driver's door with the key, then the rest with the remote? Or lock the rest from the passenger door if the remote doesn't work...

It still sounds like a bad earth, you could try pulling the loom out of the door and see if it's something obvious. Failing that you really need a meter - You can just get a continuity tester but a proper multimeter is a lot more versatile. There's all sorts available for around a tenner, for preference get one with crocodile clips as well as probes (or you'll need 3 hands...) and a sounder for short circuits which will save you watching the damn thing all the time. Set the meter to the ohms (Ω) scale, with nothing connected it should say infinite (my Fluke says overload), if you touch the probes together it should say near enough zero - this is what you want for testing the wires. (Btw it's ass-about-face for an analogue i.e. zero for open circuit and infinite for short). Pull the connector off the module (you must be getting good at that by now ) and put one probe on the end of wire M620whatever and one on a known earth (good places are the ignition lock or the door check strap), if it says near enough zero then we need to think of something else, but if it still says infinity then further investigation is required. I'm not exactly sure where this white connector (16v BA) is but this would be a good place to check next - check between the end of MPVP going into the car to your earth again and the end of MPVP and the module connector, you should now see what part of the loom your fault is in...

No idea about the stuck lock, you could try popping the rod off and seeing if it turns with nothing on the end.

[DaveyRapier]

Can you not lock the driver's door with the key, then the rest with the remote? Or lock the rest from the passenger door if the remote doesn't work...

It still sounds like a bad earth, you could try pulling the loom out of the door and see if it's something obvious. Failing that you really need a meter - You can just get a continuity tester but a proper multimeter is a lot more versatile. There's all sorts available for around a tenner, for preference get one with crocodile clips as well as probes (or you'll need 3 hands...) and a sounder for short circuits which will save you watching the damn thing all the time. Set the meter to the ohms (Ω) scale, with nothing connected it should say infinite (my Fluke says overload), if you touch the probes together it should say near enough zero - this is what you want for testing the wires. (Btw it's ass-about-face for an analogue i.e. zero for open circuit and infinite for short). Pull the connector off the module (you must be getting good at that by now ) and put one probe on the end of wire M620whatever and one on a known earth (good places are the ignition lock or the door check strap), if it says near enough zero then we need to think of something else, but if it still says infinity then further investigation is required. I'm not exactly sure where this white connector (16v BA) is but this would be a good place to check next - check between the end of MPVP going into the car to your earth again and the end of MPVP and the module connector, you should now see what part of the loom your fault is in...

No idea about the stuck lock, you could try popping the rod off and seeing if it turns with nothing on the end.

No I can't because the drivers door is still operating when the passenger door lock button is pressed, then they all unlock again straight away.

Thanks for the advice I understand what you are saying (thankfully ) I will try and get my hands on a multimeter then as you say check from a pin on the locking module connector (any pin?) if I get a fault then I will separate the door loom from the car loom and check at that end for an earth fault.

Wish me luck!

[steve_earwig]

Oh bumholes, I forgot they were bouncing open again It would figure if the BSI is looking for an earth when the door is shut...

Test the earth wire (starts with M) because everything else will be testing into the BSI - if you're going to test them all put the meter on the volts setting first or it'll go pop. Make a note of what wire you get what volts on, then check for earth on all the wires that you didn't get any volts on.

[DaveyRapier]

Do I do this with the door open or closed?