Mk7 central locking fuse blowing

[Z1ggy]

Hi all
Been on forum for a while but this is my first post.
I have 2007 mk7 transit minibus I'm converting into camper.
The problem I have is that the central locking fuse is blowing.
This happens when I try to unlock cargo area.
If all doors are unlocked, I can lock them all with lock button on remote.
I can unlock driver and passenger doors with remote top button.
When I try to unlock the side and rear doors with the 3rd button, doors unlock but also blow the fuse.
I assume I have a short somewhere.
Checked the cables at the back door and all look fine, actually in great condition.
I unplugged rear lock, tried to unlock and still blew fuse. I'm assuming that rules out the rear lock.
Same scenario when unplugging side door actuator.
Not knowing how the wire looms are routed or which colours to look for I'm stuck.
So I'm looking for some answers to a couple of questions if anyone can help.
1. Where do the cables originate, I guess behind the glove box somewhere.
2. What colours are the cables to these locks.
3. As the side and rear locks are linked, do they have common cables or are the cables totally separate from source.
4. common places to look for damage.
5. Which cable is it that sends the unlock signal to those locks.
6. Does anyone have a drawing for central locking system.
I think thats everything
Any help would be appreciated.
Thanks

[Z1ggy]

Anybody

[tranmx2]

As a fuse has blown it is likely that a live wire has touched earth or another earthed wire.
Have you made any alterations to the vehicle. Especially using self tapping screws which can penetrate a harness, cable, wire and an electronic box.

On mine there are wires in a harness on both sides above the cab. The harness on the drivers side (rhs) goes to the sliding door rhs and then to the drivers rear door rhs and maybe across to the lhs of the vehicle.
The harness on the lhs goes to the lhs sliding door and maybe to the lhs rear door.
It's controlled by the BCM.

It seems that Ford do not give wiring diagrams.
The info' I have found on the web does not seem to apply to my vehicle.

Did find one the other day a link to it was given in a post by me. https://cardiagn.com/ford/transit/

In a post a web page is referred to from which for a fee info' can be copied.

[Z1ggy]

Yeah, pretty sure there's a short to ground somewhere.
I have made alterations but was very careful of where I was putting screws.
The fault was there when I got van. There is a sticker with an asterisk on it right below the c/l fuse which made it handy to find. I guess it was happening pretty often for someone to go to the trouble of labeling it.
Guess I'll have to try and trace all the cables from the locks backwards. I just don't know where they come from. Guess I'll find out.
Cheers

[tranmx2]

Within the front doors and within the body are connectors - at the upper hinges. Within the rear pillars are connectors - when you have figured out what's what continuity etc can be checked.

[Z1ggy]

I found the multi plug under dash on the drivers side and unplugged it.
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I then opened up the rear offside light cluster. Theres two connectors go to the door, 1grey and 1 black.
I tested all cables from loom connector to ground expecting infinite resistance as front plug was disconnected.
I found about 5 of them were short to ground. 1 from the grey plug and 4 from the black plug. There is a local ground behind the rear lights, I disconnected these cables from chassis but results were still same. Does this seem right. I've noted them on next image which has the cabling from light cluster to door cabling mapped out.
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Boxes represent plugs. Numbers inside boxes are the pin numbers (was really difficult to make them out) and numbers outside boxes are black cables and where they terminate into the plugs.
If anyone can help out, I'd be most appreciative, it's driving me nuts.
Cheers