Help me break in to my C3?

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My Name: Rogerborg

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After the battery ran low, the BSI went bonkers and now the deadlocks are aply named: they're trying to kill me. None of the doors can be opened from the inside. The remote can unlock the boot, and causes the door solenoids to clunk when locking (but not unlocking). I can get in to the car, but only by manually opening the driver's door from the outside (and using the outside lock). Obviously, I can't take passengers in it.

I've tried all the various version of BSI reset on the intartubes, none of which change anything. My local sparky struggled with it for 3 days then admitted defeat.

Citroen want £100+ just to plug the BSI into a computer and then inevitably tell me that it's bust and I need a £500 replacement. Not happening. I might give in and send the BSI off to BBA Reman, but it's an 8 year old Citroen, it's really not worth spending money on. It's barely worth more than scrap as it is. My preference is to get the doors open any way that I can then take the panels off and simply unplug the motors so that they can't be locked again.

tl;dr version, does anyone have experience of opening the doors on a C3? Can it be done with a slim jim, or are they well protected against that? Any suggestions for getting them open? I have access to the inside of the car, but the panel screws aren't accessible.

And it's a long shot, but I might try shoving 12V directly down the lock wires. It's not obvious from the Haynes Book of Lies which circuit(s) opens the locks though - can anyone advise?

Cheers.


EDIT: (to cut a long story short :D )
BSI Central Locking Relay repair topic is here to read
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My Name: C3driver52

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Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4 i
Fuel Type: Petrol
Mileage: 79984
Trim Level: VTR+
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: TU3 (75 PS)
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Hello Rogerborg, welcome to the C3 forum.

Sound like you have been having fun :D

There are more instructions on resetting the BSI here

One more try won't hurt?

Have you replaced/checked fuse F16 (30A) on the fuseboard in the glovebox

Check/replace the relay(s) on the fuseboard that control the central locking motors.
(relay - I have heard one click on the BSI when the locking engages etc, it appears on the diagram, but seems to be inside the BSI - I can feel it change over when locking/unlocking, but I can't see it)

There is also a relay for the child locks, but I don't know where it is on the car.
EDIT: the child lock relay is above the diagnostic connector in the glovebox area. Very well hidden and difficult to get at.

I have had quick look at haynes and come up with this:
(its a work in progress)


"If you want to bypass the computer for unlocking/locking, then I would try it this way.

Disconnect the battery,
access the fusebox in the glovebox (the BSI) and remove the 16 way grey connector

Image

This will give you access to pins 13, 16 and 15 in the PLUG (White, Red and Brown wires) these give the power to the various door motors."

Image
Citroen C3 Central Locking BSI Plug and Socket
Citroen C3 Central Locking BSI Plug and Socket
My Name: Rogerborg

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Hi, thanks for the great response.

I've tried replacing all the fuses (I've had quite a few goes at sorting this) but will double check F16. My garage bloke also tried the fuses and "replaced a couple of relays" although I'm not sure what ones - I also can't see any obvious candidates on the outside of the BSI. He was keen to find the cause - at his own time and cost! - since they specialise in electronics and wanted to know how to sort it out in future. Eventually he had to admit defeat, and seemed genuinely gutted.

On the BSI reset, I had another few tries again today, using all 6 combinations of ignition (key in but no turn, one turn, two turns) and lights (side lights, headlights) with no luck. There's no indication of any change in behaviour - the same generic instructions are supposed to produce a tone when resetting the BSI in Peugeots, but I don't get any feedback from mine.

I should have mentioned, the child lock dash button is illuminated permanently, but all four doors are deadlocked. It's just occurred to me that perhaps I should unplug the child lock relay (36 in the Haynes Book of Lies) but I'm not sure where it's located, whether it's behind the switch on the dash or down near (or on) the BSI. Any ideas?

Both the child lock button and central locking button on the dash produce clunks from the locks when pressed, and will deadlock the driver's door again if it was unlocked, so there's power to the close side of the circuit at least.

The connector advice is brilliant, thanks. I was eyeing up pin 16 (red) as a likely target, because, you know, always cut the red wire. But on a closer look at the Book of Lies, you're right, that only goes to the front locks. It's white and brown that go to all 4. I'd been stumped by the apparent lack of an earth wire to the motors - it had never occurred to me that the circuit might just drive them in reverse. :oops:

The "Caution!" in the Haynes about the actual wire colour being irrelevant gave me pause for thought: these new fangled techno circuits are a bit beyond my simple brain. But I think I can handle finding two wires on the plug and shoving 12V down them one way or t'other. I'll give it a try and see if I can get a response out of the locks. If you don't hear from me within a week, please send Lassie to fetch help. :!:
My Name: Rogerborg

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MISSON partially ACCOMPLISHED

I can't thank you enough for that wiring advice. It was indeed 13 (white) and 15 (brown) and they do operate the motor both ways. IIRC, I put +ve down 15 (brown) and -ve down 13 (white), but there's only one other option to eliminate.

The lock mechanism is pretty funky though, because I still couldn't open the (front) doors from the inside until I'd first opened them from the outside. The rear doors still can't be opened from the inside as the child locks are engaged - the dash button is still illuminated and stays that way. The root misbehaviour is still present: with the BSI reconnected, I managed to lock myself in again, but it was the matter of moments to manually power the locks again and escape. I've just taken out the F16 fuse now so there won't be any more nasty surprises.

So now I'm on the hunt for the child lock relay, which doesn't appear to be on or near the BSI. I half suspect that's what's causing the lock-of-death problem, but at the very worst case I can get the rear doors apart now and apply some percussive maintenance to the problem.

And again, thanks, that has saved me an enormous amount of pointless expense. And a hope the Citroen genius who came up with that locking mechanism gets a dose of nob rot for Christmas. :D
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My Name: C3driver52

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Joined: Sat Apr 30, 2011 7:40 pm
Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4 i
Fuel Type: Petrol
Mileage: 79984
Trim Level: VTR+
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: TU3 (75 PS)
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Great going Rogerborg,

you seem to be a step ahead of me, but I will post my work anyway as it may be useful for someone.


I have produced a matrix from a known working locking system on the Citroen C3, taking states from pins 13, 15 and 16 on the grey 16 way plug on the BSI. The motors to lock/unlock/deadlock are driven by short +12v pulses, one pulse per operation.
Citroen C3 door lock BSI output matrix
Citroen C3 door lock BSI output matrix
It does look like the childlock relay is worthy of attention, I can't see the relay, but, I can't see the child lock switch on the diagrams either!

If the child lock relay turns up OK, or doesn't turn up at all, it will be good to see the matrix of your car. Sometimes you can see a stuck line. You may end up whipping out the BSI unit and replacing the relay inside.

Happy hunting
My Name: Rogerborg

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Willco, I'll update this when I've found the child lock relay. At the moment, the car is under a foot of snow, so it likely won't be for a while though. :D

Your matrix looks good, except I assume that you took these readings relative to a vehicle earth? I'd note that since there's no earth to the motors, the potential difference has to be supplied down the other wire. i.e. it's not just +12V to 13, it's +12V to 13 and earth to 15 to engage the locks, or +12V to 15 and earth to 13 to unlock.

I can't recall offhand what forms the other side of the 16 circuit. I'm not that fussed about it since it only goes to the front locks and my front doors are currently OK, so I'd hesitate to fiddle with them. I also haven't actually checked the voltages at the BSI connector, I'm just going by what happened when I unplugged the 16 pin connector and put potential across the wiring.

The rear child locks are powered from a different connector / relay, and I suspect that's my problem. I'd infer from the Haynes diagram that the child lock relay is external to the BSI, since it's shown separately on the diagram and remote child locking was an option, at least at the design stage or in some markets, as there's a blanked off manual child lock switch in the back doors.

I haven't found it yet, but my stereo removal widget arrived today so I'll be able to follow the wires from the dash switch and see if I can track it down that way. I'll update when I have more info.
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My Name: C3driver52

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Posts: 1877
Joined: Sat Apr 30, 2011 7:40 pm
Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4 i
Fuel Type: Petrol
Mileage: 79984
Trim Level: VTR+
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: TU3 (75 PS)
Has thanked: 89 times
Been thanked: 66 times

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You are right in assuming the reading were taken relative to vehicle earth.

I know citroen do some strange things, but they do follow convention on earths so far in my exploration.

I can see the earth for the rear door motors is via the child lock relay (pin 4 and pin 3 of the child lock relay)

My leap of faith is that the BSI sinks the current for the other motors via the BECEA line (pin 5 of the child lock relay) and pin 8 of the BLACK 16 way BSI plug as and when it feels like the motors should run or not.

This would give the child lock switch priority over the BSI for the back doors.

Anyway, thats just my ideas, not based on any testing (yet)
My Name: Rogerborg

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Bleeping Citroen. Wherever they've hidden the child lock relay, it's too cunning for me. It's not on the BSI (although there is a relay in there that trips when pressing the child lock dash button). It's not in the secondary fuse/relay box next to the battery. There's no 5 pin connector in either location to be a candidate. I've checked continuity to all the pink wires that I can find anyway, from the BECEA pin 8 of the 16 pin black connector on the BSI. Trying to follow that wire, it vanishes into the loom and I can't see it coming out anywhere. The Book of Lies doesn't give any clue - I wonder if a proper workshop manual might.

[UPDATE]

I'm out. I took the panels off the rear doors and whacked 12V into the child locks manually (white and blue wires, the top two on the connector). Job done, I've disconnected the electrics from the rear doors, and fuse 16 is still out so that should be me sorted, in the sense of having doors that don't lock rather than doors that don't unlock.

It does appear that the motors are not earthed, and therefore do need potential across 2 wires to actuate them.

After reconnecting the battery, the child lock light is now off, so it's possible that the problem has resolved itself. I may have another poke at it, or I may just leave it, since I can live with it and the car is hardly worth selling on anyway.

Thanks again for the socket info, it was just the kick up the arse that I needed.
My Name: Rogerborg

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For future reference, I've just had a reply from Haynes saying:

"The child safety lock relay is mounted above the fuse box and to the left of the diagnostic socket."

I couldn't see a candidate there the last time that I looked, but I'll have another poke around. If I find it, I will commit to never referring to Haynes as the "Book of Lies" again. ;)

EDIT: Added a picture of the child lock relay hidden behind the glove box - I had to remove the glove box to get this picture.
Child Lock Relay Location on Citroen C3
Child Lock Relay Location on Citroen C3
My Name: Rogerborg

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Joined: Fri Dec 02, 2011 1:56 pm

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Ah, the child lock relay (marked as a Bitron 232303) is located directly above the diagnostic socket, very well hidden under a curved plastic shroud which seems impossible to remove fully. I eventually got to the relay from the side with a pair of mole grips, it just pulls straight out of the socket.

However, with the child lock relay out, there's no change in behaviour, I can deadlock lock myself in again.

The dash child lock light is at least out now but I reckon it's a BSI reman job to fix it, i.e. probably not worth it. I'll just live with permanently open doors. Fun times. :D
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