Cig lighter socket fuse

[paradox1001]

The photo I uploaded isn’t showing for some reason

[Sol]

The fuses are mounted on the top surface of the BSI (facing you), but it's a rats nest of wiring in there, and as John says, get some surgical clamps, forceps, hemostats etc as the fuses are very hard to get to and to pull or refit.

That is with the entire glovebox removed, otherwise you cannot get anywhere near them. The BSI is mounted behind the glovebox outer housing itself.

[paradox1001]

The fuses are mounted on the top surface of the BSI (facing you), but it's a rats nest of wiring in there, and as John says, get some surgical clamps, forceps, hemostats etc as the fuses are very hard to get to and to pull or refit.

That is with the entire glovebox removed, otherwise you cannot get anywhere near them. The BSI is mounted behind the glovebox outer housing itself.

Thankyou Zion

I’ve not managed to get round to removing the glovebox yet.

My original problem of the car not starting has returned but it’s intermittent 
I took the car back to the garage and they say it will need a new body control module due to water ingress.
They say they can’t do it and it will need to go to Citroen and cost over a £1000 just for the module 

Does the body control module even control the starter motor and if so where is it located and how could water have got in.

[Sol]

Ok, so in Citroen world the body control module is the BSI...Body Systems Interface. Only Ford call them BCMs.

The BSI reads the key's rolling security code, from the transponder chip in the key body, which needs no battery power, but is powered inductively using a loop built into the ignition barrel. Once that chip powers up, its code is read by the Comm 2k unit which controls the steering column switches etc. Then the BSI which is in charge of the Comm2k checks the key security code is valid (the BSI is also the immobilizer and network bridge for all other systems) and if it is valid, when the engine ECU receives a request to start from the ignition, it asks the BSI for authorisation to start. If yes, all is well. If not, you would have a flashing key symbol in yellow on the dashboard I'm sure (not seen the Citroen version of that icon but most vehicle will do this) and it will not start.

How they diagnosed water ingress I don't know. A BSI from Citroen would be well over £1000 I am certain. Water can get into it from a windscreen leak or jetwashing it with too much gusto.

I would get it scanned for codes using a reliable pro scanner or Diagbox, post the codes and we can go from there.

They are correct that if the BSI is corrupted then only Citroen or a specialist can recover that. There are independent folk who can recode a used BSI from your original but are few and far between.

I'd hold off till you know for sure what had happened, I wouldn't rush to Citroen. Could be a bad or worn ignition barrel, dislodged transponder chip in the key from a clumsy battery swap, wiring chewed by mice, or water ingress also possible for intermittent behaviour. Sounds like they are guessing, just like we are.

[paradox1001]

He said it was water ingress because a wire had corroded on the bcm and failed
Apparently he re soldered the connection
The car started fine after that work was done
But shortly afterwards the starting got intermittent
The thing is sometimes when it won’t start I can hear a slight click from the starter solenoid
This would indicate that at least some voltage is present at the starter.

[paradox1001]

I’ve asked on the forum if there’s anybody near by with diagbox
A point that maybe worthy of note is when it won’t start on the key it bump starts no problem.

[Sol]

Ok so I'd be thinking it's an issue with the starting system, nothing to do with the BSI at all.

The key starting position triggers a relay and it in turn, operates the starter solenoid itself. In the engine bay fusebox it is relay R8, which may be hard to replace as they aren't marked, but is in the bottom of the fusebox on the schematics.

That's where I would be looking. I'll attach a schematic in a minute. Check the whole circuit if you can, starting with the heavy cables and then the little wires as you may just have a bad starter or bad wire to it, and bump starting works so it's not an immobilizer or BSI issue. Make sure the heavy positive and earth cables are good, have clean connections and are not corroded or frayed.

If those are good, check the small wiring between the engine fusebox and the starter solenoid. If that's good, check the wiring from the ignition switch to the engine bay fusebox.

Ask the garage to point out the wire they repaired. If they go to the engine bay, you can educate them that the "body control module" is behind the glove box, and has nothing to do with starting the engine other than it contains the immobilizer. The corroded wire could be in the starter control circuit or the engine ECU itself. (Mounted next to the battery)