ok- well here's the story then;
once upon a time, during one of the first service-outings for the Cup, when it was getting the inherited niggles sorted- it was established that the A/C control panel wasn't acting upon the mixer-valve for cabin ventilation heat.
Various things were tried and in the the end it was unavoidable that the controller (panel) itself was going to have to be replaced. The unit was £700+ at the time, and I think I had the airhorns replaced at the same time.
I've always tried to collect cast-off bits of the car, whenever they are swapped out (I drew the line at the airhorns!) but I asked Glenvargill to retrieve the A/C controller from the bin in the workshop. They seemed bemused, but did so, and off I went.
Over the weekend, I realised that I now couldn't get the A/C to actually turn off; it was running all the time- all other functionality was correct.
I went back to see Glenvargill and they told me that 'some Ferraris run with the A/C on all the time', but I pointed out that the car had had never had this functionality before.
A date was established for the car to return for the fault to be investigated, but in the meantime I took the top off the A/C controller that I had rescued from the workshop-bin and could see a large PROM-chip in a socketed location on the PCB. Clearly some kind of programmed 'firmware' (for want of a better analogy), complete with version No & date.
I had already tried to cultivate a good relationship with the workshop-guy who looked after my car, and knowing them to already be somewhat befuddled by the fault, I asked his opinion for a change of the chip within the controller.
They looked into it, and he swapped the chip between the original and new-replacement unit; and Hey-Presto; everything worked!
I still have the old unit, which wouldn't adjust cabin-temp, now fitted with the newer crackers-chip.
David Askew has a test-rig for this stuff; he would be able to establish if the controller from the Zagato was functioning correctly in the 1st instance. You should definitely discuss it with him over the phone.
If the system needed a recharge, would it affect the radiator fans..? Not likely - these systems have a pressure-switch which will inhibit operation if there is too much or too little pressure in the system. I can't see how incorrect pressure would bring the fans in...
Two-weeks to MOT for me. I need to start the car this week, and start to make preparations...