Squeals/squeak Aircon

Ok, every time I turn the engine off I get this squeaking noise coming from the passenger side engine bay, the squeak last for about 3 seconds. So I started the engine, turned off the air con with the engine running and the squeak begins for 3 seconds and dies off. (had the Aircon re gassed last month)any thoughts what it could be?
 
Mine does this sometimes, even with just normal heaters on. As soon as I turn it to zero it stop after a few seconds.. Not sure if it's just the fan spinning.
 
could be cooling fan it runs at low speed when the air con is on to pull air over the condenser