Bought a 97 Deville, 90K miles,last week. Test drive went fine but now (like they didn't know) the ac will sometimes come on, run a few minutes, then go off for anywhere from 30 seconds to ten minutes, then come back on. Once it comes back on, it stays on forever. Blows very cold. Seems to be worse after the car has been driven for an hour or so. If you start the car cold, the air comes on, and will stay on indefinitely but if you stop, park, then restart, it may or may not come on. While the fan is not blowing, the compressor is cycling on and off normally, just no fan. I know next step is to put a test light on the fan power but thought I would ask. Thanks.

 

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you answered your own question