Battery draining! + central locking issues

Hi everyone. My c3 has brought forth a real clanger this week. I first noticed a problem when I tried to unlock my car using central locking yesterday morning and it would not respond. So I opened the door with the key and when I turned on the ignition it said 'eco-mode'. The central locking then started erratically locking and unlocking by itself. I sat in the car for five minutes doing nothing with the ignition off and at various points the central locking would go mental.

I took it for a long drive down an A road to charge the battery and when I got home it was fine, however the next morning, the car was back in eco mode! Central Locking not responding.

My car is a 1.4 '53 HDI
There are no aftermarket parts, and the only thing I have changed recently would be the headlamp bulb. I didn't know how the clip that holds the headlight in works, so I just jammed it in somehow since I couldn't see it. Could the metal clip be draining the battery somehow? I am only asking because when I fiddled with the back of the headlamp, 5 times out of 10 the central locking would activate /deactivate.

This doesn't make any sense to me and any help would be much appreciated . Thanks

I have read many threads, checked the battery in the key fob, tried reprogramming it, none of which had worked. Losing hope for my little car

Hi C3B3LLA, it sounds like the battery is not holing charge overnight, so after sorting out the headlamp clip, try a new battery.

Euro Car Parts have the correct battery for your C3 and offer free delivery, there are also some good deals on ebay

There a some pictures of the headlamp clips in this topic: https://citroenc3owners.com/citroen-c3-t ... -t134.html

Hi there.
Since the previous post, I have left the battery disconnected overnight and when I reconnected the battery the next morning, it was fine, no eco mode! I can only conclude that the battery is fine(?) And that something is draining it when connected.

I will check that the headlamp clip is properly connected, but even when I reconnected the charged battery, the central locking still doesn't work. Really unsure what to do.

Might try leaving the battery connected tonight but leaving out some of the fuses to try and pinpoint what is causing this.

Any other ideas would be appreciated.

C3B3LLA wrote:Since the previous post, I have left the battery disconnected overnight and when I reconnected the battery the next morning, it was fine, no eco mode! I can only conclude that the battery is fine(?) And that something is draining it when connected.

Eco mode is controlled by the BSI, if you disconnect the battery then you disconnect the power to the BSI and No BSI functions will work - hence no Eco Mode. I disagree with your conclusion

C3B3LLA wrote:when I reconnected the charged battery, the central locking still doesn't work. Really unsure what to do.

Does the the button on the dashboard lock and unlock the car when the remote control doesn't?




You can work out if the fault is the central locking or the remote control of the central locking.

The central locking is controlled by the BSI and is central locking is well know to give problems.

C3B3LLA wrote:I will check that the headlamp clip is properly connected,

Good idea

The button on the dashboard does usually lock and unlock the car (at the moment I am using the hand through the window technique to lock the car... but it doesn't always! Sometimes the car will randomly lock itself when I'm inside and the only way to get out is to use the key from the outside; the door handles and dash button do nothing!

I have also recently been told by my neighbours that, at several points during the night, the hazards will flash frantically by themselves for long periods of time as the central locking activates, trying to lock the car when it is already locked - guess I've found out what's draining the battery.

I'm guessing this a fault with the central locking, or two crossed wires or something but am not sure how to proceed from here.

Is it worth just taking to a garage and explaining everything?

C3B3LLA wrote:I'm guessing this a fault with the central locking, or two crossed wires or something but am not sure how to proceed from here.

The central locking is controlled by the BSI module (its the fuse box in the glovebox). There are some pictures of it here. Looking at the connections to the BSI (by disconnecting and reconnecting them), looking for water ingress or damage to it would be a good start. Some BSI modules can be repaired and all can be tested (try contacting BBA Reman via their ebay store). BSI removal tips are here.

If you wanted to understand or investigate the wiring for the central locking outside of the BSI, the Haynes Manual has some good circuit diagrams for the C3.
Arrowed is the central locking connection to the BSI, disconnect, inspect and refit this plug.

Hi, thanks for the great response. I checked this, but nothings changed unfortunately. I brought it to the garage and they told me that the problem could be with the fusebox (the one under the bonnet) and that I should get the whole thing changed. Does this sound likely?

I see the central locking outside my window at the moment, activating. It only ever activates to lock or re-lock the car thankfully, so I don't have to worry about it unlocking itself. Sometimes it happens when I'm inside and completely deadlocks me inside the car.

But yes, could the problem be with the engine bay fusebox?

C3B3LLA wrote:But yes, could the problem be with the engine bay fusebox?

I would imagine the garage have done some testing, where I have not, so I would go for their diagnosis over mine. My first choice for fuse boxes at fault would be the one in the glove box as this deals with all the security, but the garage thinks its the engine bay one (BSM) and they have seen the car....


The advantage of the engine bay fuse box is that its not coded to the car and relatively cheap to buy second hand, they are available on ebay, like this one. There are also instruction on removing the engine bay fuse box (BSM module) from the car, in this topic.

Pick a BSM from a similar year and specification of car, even other Citroen and Peugeot models have suitable BSM modules for the C3.