The only way to get to the multiplugs that connect to the resistor and the fan motor is laying on your back in the foot well.
Turned out nothing wrong with fan or resistor when bench tested. Just loose multiplugs from regular passenger kicking.
What cretin at FIAT decided to put two fragile plugs where passenger feet go, with no protection?

Anyway all working now.

I wonder how much a dealer would have charged for a new fan and resistor?