backprobe and check the voltage on pin 64 of the ECU let me know what you find
Does the temp gauge work correctly?
also try grounding pins 17, 42 and 68 individually, with the ecu disconnected, and key on and see if the fans run.

Problem solved. The red/green wire, which should have 12v ignition, did not. There must be some break in the wiring between the fuse under the dash (where it does) and the relays, so I've rerun this wire and now the fans work perfectly.