Citroen C2 - dead electrics - No power to locks, interior light, ignition - everything dead

[Hell Razor5543]

You have gone from a major problem (a car that will not start, nor shows any inclination to do so) to a minor problem (issues with some of the ancillaries). That is definitely a big step in the right direction.

[Dormouse]

time to sit back, have a cup of tea and let the gnomes cogitate. We at least now know the BSI has some life up stream. Lets find the downstream issues now.

[wheeler]

Not really sure that it gets us much further here, as i said in a previous post it doesent really prove anything. This could still very much be a BSI fault. Powering up the F13 is only bypassing the internal relay 7. This relay is triggered internally by the BSI but again triggering may rely on a signal from elsewhere so could still even be a wiring fault too.

[Dormouse]

That one isn't for a C2, so maybe Wheeler got the wrong one - it can happen with multiple requests.

This is the correct one for 'Napping's' C2:

Within the BSI is a clear earthing ring that connects through one single point inside through connections 6 & 8 to both MC32 and MC30 If you can reach that ring inside and earth it you will test if the earthing connections are disconnected/faulty. I think it is well worth checking this earth ring

[napping]

So - the BSI plays dead unless BSM relay R6 or BSI relay R7 are bypassed. That suggests to me whatever triggers relays R6 and/or R7 isn't doing its job.
The odometer not displaying whilst the tripometer does suggests there is no power to the circuit(s) that activates when a door is opened, etc - as usually the odometer will display before the key is inserted in the ignition switch. So the problem appears to be related to the initiation stage where the power is available to the locks and the odometer. As Wheeler says, this could be a cable issue.

[Dormouse]

I am suspicious that MC30 is not functioning but MC32 should connect it inside the BSI unless that connection is faulty.

[wheeler]

Within the BSI is a clear earthing ring that connects through one single point inside through connections 6 & 8 to both MC32 and MC30 If you can reach that ring inside and earth it you will test if the earthing connections are disconnected/faulty. I think it is well worth checking this earth ring

What do you mean by earthing ring? Yes I would definitely confirm pins 6 & 8 have a good earth (I would check them under load if it was me). Has this not already been checked?

[Dormouse]

Yes but pins 6 and 8 connect up inside the BSI to the earth ring and there are multiple earthing connections going out to all of the services on the same connection - for instance R6 internally or flasher/hazard unit 23 externally via pins 13 and 14.

IF, just IF, this earthing ring is disconnected from MC30 & 32 then none of the switching earths for the BSI will work - Hence no control as well as activation

[Dormouse]

I hate these diagrams as most people find them confusing - me included. All for the want of a designated colour or style exclusively for live, feed and earth wiring. Once you understand it, a wiring diagram is ok but for people not regularly working with them (especially remotely when you have nothing to physically look at) it is a nightmare.

[napping]

I am suspicious that MC30 is not functioning but MC32 should connect it inside the BSI unless that connection is faulty.

I can try testing BSI green plug Pin 8 to earthing point MC32, and BSI green plug pin 6 to earthing point MC30. Also BSM 28 point grey plug pin 19 to earth MC 30 - just to rule these earthing points out as the cause. If, as is likely, it's not these earths, what next?

[Dormouse]

Book into rehab!

Let's cross that lot off the list first.

You must have the Patience of a Saint as well a double jointed to get into all the nooks and crannies.

[napping]

What do you mean by earthing ring? Yes I would definitely confirm pins 6 & 8 have a good earth (I would check them under load if it was me). Has this not already been checked?

Yes, I checked them for continuity but not under load.

[wheeler]

Can you confirm by earth ring are you talking about the line i've highlighted in green?

[Dormouse]

Checking the wiring & plug pins to earth/ continuity proves the harness is ok. With the plugs out test for continuity between pins 6 and 13, 14. Then pin 8 and 13, 14. Then pin 6 to 8. Lets see what that gives. Humour me.

[Dormouse]

Can you confirm by earth ring are you talking about the line i've highlighted in green?

Yes. That ring connects multiple earths/returns and IF, just IF, 6 AND 8 do NOT connect to that ring there will be multiple failures