It's common knowledge that these looms frequently give trouble in mk2 Fabia and others with similar connector/boot type, and it's not too tricky to eyeball the wiring under the rubber boot for obvious breakages in the door hinge area.
Measuring wires end to end with a multimeter to check continuity may add reassurance that the wiring is really intact, and potentially help to locate faults to more exact locations. For example, the door lock module.
If all the wires are measured as reaching their destinations it may save unnecessary loom replacement, or confirm loom fault if they don't.
The photos and tables here relate only to one particular variant of loom, with part number 5J0971120GK from 2012 (the letters at the end being not always simply a 'revision number' but may actually be the only difference in the part number of functionally different loom variants). Thanks go to @jps711 for permission to use this loom for photos and information gathering during repair.
If anyone wishes for info on looms with different part numbers, I may be able to help find the differences, and would welcome any unwanted/broken looms that might be cluttering up anyone's garages/sheds since replacement. For each I might receive I'd do dedicated wiring tables, with cross-checking against circuit diagrams. It's not completely straightforward to find the info via the circuits, as they are grouped by functions (e.g. mirrors, windows, locking), not 'here's the wiring diagram of the whole drivers door' for example.
This is the area that always contains the faults, due to a poor design where the loom just bends back and forth with door movement, rather than a twisting action as used on earlier cars, with a vertical dog-leg in the rubber boot.
The photos and wiring tables are from the 'destination connectors' points of view. I strongly recommend using short pieces of solid wire to temporarily insert into connectors at each measurement point, as many mulitmeter probes are not sufficiently fine to go in far enough to make good contact. Double check that the meter hasn't 'gone to sleep' or otherwise malfunctioned any time you don't get a beep when expecting one, do this by shorting the two probes to each other.
This is the pin numbering arrangement of the door disconnect connector, viewed on the mating face. Be aware that the rotating orange latch needs to be in the open position to disconnect and reconnect this from/to the A-pillar male counterpart. Attempting to refit with the latch in the wrong position will fail, and can cause pin damage, possibly.
On to the nitty-gritty of the pinouts. All photos are as above, of the mating face of the connector, observe the housing features to ensure same orientation:
Pin number at this connector
Wire colour(s)
Pin number at 28-way door disconnect, and/or other conn
1
Blk/yel
9/28
2
Wht/blu
6/8 at mirror conn
3
Brn
16/28
4
Gry/blu
8/28
5
Blk/blu
7/28
6
Wht/grn
11/28
7
Wht/blu
7/8 at mirror conn
8
No connection
9
Grn
12/28
10
Wht/grn
8/8 at mirror conn
Pin number at mirror interconnect connector
Wire colour(s)
Pin number at 28-way door disconnect, and/or other conn
1
No connection
2
No connection
3
No connection
4
Blk/red
13/28
5
Brn
16/28
6
2x Wht/blu
10/28 and mirror sw 2/10
7
Wht/blu
mirror sw 7/10
8
Wht/grn
mirror sw 10/10
Pin number at loudspeaker connector
Wire colour(s)
Pin number at 28-way door disconnect, and/or other conn
1
Brn/blu
22/28
2
No connection
3
Blu
21/28
4
No connection
Pin number at Int monitor switch connector
Wire colour(s)
Pin number at 28-way door disconnect, and/or other conn
1
Blu
17/28
2
No connection
3
Red/blk
15/28
4
Brn/yel
18/28
Pin number at WM connector
Wire colour(s)
Pin number at 28-way door disconnect, and/or other conn
1-3 inclusive
No connections
4
Grn/blk
window sw 4/4
5
Gry/wht
5/28
6
Wht/blk
window sw 3/ 4
7
Brn
16/28
8
Thick brn
24/28
9-15 inclusive
No connections
16
Thick Red/wht
25/28
Pin number at window switch connector
Wire colour(s)
Pin number at 28-way door disconnect, and/or other conn
1
Brn
16/28
2
Gry/blu
8/28
3
Wht/blk
6/16 at Window Motor
4
Grn/blk
4/16 at WM
Pin number at lock connector
Wire colour(s)
Pin number at 28-way door disconnect, and/or other conn
1
Brn
23/28
2
Blu/yel
1/28
3
Vio/yel
2/28
4
Grn/yel
3/28
5
Yel/brn
4/28
6
Brn
16/28
7
Yel/blu
6/28
8
No connection
Please let me know if you find errors or omissions in the above, or if you know how to format it so the tables are alongside the photos!
Cheers
Pete