ABS + ESP Fault 2006 Mondeo ST

[Keiranpm]

I've got an error C1155 for the front left ABS wiring, it was previously fixed by a garage which patched a bad wiring repair. This time they've said because the wiring fault isn't on the sensor side either they fix it with a new wiring harness from Ford or I fix it with wiring from a scrappy who has a mondeo.

I've only been driving for 2 years and been interested in DIY car repairs at an amatuer level. I've done a clutch replacement on my focus so I would have thought a wiring job wouldn't be much more difficult.

Has anyone got any advice on how to bug fix the continuity of the ABS wiring and also how the hell I find out where the wiring is going without ripping out all the upholstery and wheel arch cover etc (any online repository of wiring path diagrams of something like that).

Note: the warning has only appeared since we've had a cold snap which saw temperatures drop to -3 and when performing an ABS test in diagnostics I hear the right caliper fire but the left does nothing. maybe moisture is getting into the wiring loom?

Any tips for a newbie would be greatly appreciated 👍