Possible Broken Wire in Loom

Previous to my other threads, especially the "longer than usual crank time" one, I believe I may have a breaking wire in my engine harness loom. The reason I suspect this is due to the very cold temperature we've seen recently, the car has started up first time almost everytime. However, I did get a flashing glow plug light at the same time. However, now it is a bit warmer, the glow plug light has disappeared and we're back to cranking a while before ignition. 

I suspect that the colder temperature must've made the split in a wire in the loom contract enough to make a good enough contact in order to start up properly. I have no way of testing this theory without wiring diagrams. Previous to this I tested the crankshaft sensor which checked out fine to the respective pins on the ecu and not shorting to ground or to each other.

If someone could provide a wiring diagram of the relevant loom, I could have a go at testing this. Additionally, if anyone knows a guide to gain access to the respective loom I should be looking at, would help massively, if not I'll have a go at it myself. Thanks very much guys!