Tony i got the same problems
Drove to trax fans were fine, kicking in etc
just as i started queuing the temp started to rise sharply. Pulled over let her cool down etcetc got back in the queue and finally it over heated.
Same as you new gaskets etcetc group a head gasket.

Bridged the fans at trax, nothing.
Wired straight to the battery and they worked so the fans are ok.
Checked the fuse and thats fine too
It is a know fact the wiring can break down.
Neilm knows a guy that is making fan wiring looms that don't need any soldering and i should be getting one off him but for the time being i've got it running on a switch directly off the battery.

If it doesn't run directly off the battery your fans are fooked
Note; you can bleed the system using the bleed next to the stat
HTH