Put the pushbutton control unit in auxiliary test mode by pressing both AUTO buttons simultaneousely for more than ten seconds (it takes about twelve on my car). The engine need not be running, but the key should be in position 2.

Then watch the fans. If you see them cycling like this, the problem is either in the fan motor or the controller.

The fans don't start automatically with the AC, but turn on when any of several criteria are present. There are limits on refridgerant pressure and temperature and ECT which activate the fans.

I'm not sure if you have the N65 pulse-control module in your car or if you have the later fan control box.