Ouch Noc. If you've double-checked all your wiring, than the only thing I can think of is to trace the ECM wiring from the fuse box to source.
The rad fan wire is on a separate circuit/wiring loom, as far as I can remember. Is your rad fan relay ok, or is it damaged / stuck? You may have two separate issues. Mine melted when my fuse melted (damned cheap fuses) Try switching fan relays to see if the fan instantly turns on with a different relay.
Another possibility is that one of the tie wraps is so tight that it wore through several wires and there's a short. It's a long shot, but hey...