iMac fans stopped, what must I do?
You should certainly request help online or through the phone - (31) 0900 7777 703 - in either Netherlands or the country where your mac was originally sold. Fans are pretty easy to diagnose remotely since it's almost always the fan unit failing (or when it's not that, the next most likely cause is simply reconnecting the fan cable) so you can often ask for a parts and labor quote to help you decide what to do.
You seem to indicate it's the CPU fan. It and the hard drive fan are very hard to replace as you have to disconnect and remove the LCD panel, the logic board and many of the other parts. The optical fan is more amenable to a DIY repair. All the connectors are very delicate and if you break them, the cost to repair can be pretty large. (Think $800 to $1100 for a whole logic board). iFixit.com has good take apart manuals and once you have a quote or two from authorized service providers, you might decide to get inside to reconnect the cables and at least look around.
My advice is don't do anything yourself until you're sure Apple won't cover it by calling them first to get a quote. The main hardware warranty has great links for getting service worldwide - since it's quite long I'll pull the links here for quick reference:
- International Support Information
- Apple Authorized Service Providers
- Apple Retail Store
- Apple Support and Service Phone Contacts Worldwide
- Apple Complimentary Support
Lastly, don't be afraid to run it for short time and low CPU use to get more information and be sure which fan went out. The CPU will reduce clock rate when it gets warm, then it will go to sleep for 30 seconds if that doesn't keep it cool, next the OS will shut down (all of the above events get logged at default settings except maybe the clock rate). The CPU will also shut everything off abruptly if all of the above fail. Don't run for weeks or hit the CPU with 100% tasks and expect it to last for years with the CPU fan off, but other things will have to fail for it to be a melt / fire hazard issue. I also wouldn't run it needlessly and risk MLB failure needlessly.
I'd try and SMC reset (remove power plug) from iMac for at least 15 seconds. Then plug it back in and see if it's fixed. If not, you're going to have to bring it to a repair centre to get sorted. I wouldn't worry about attemtping to start it again - it won't melt down that quickly and it has a thermal cutout system to prevent such issues so will shut itself off before it gets too hot.
I had fans go out on my iMac (2012) and I put a high velocity fan behind it, where the air goes into that slit along the top in the back. The iMac aluminum chassis acts as a heat sink and the fan cools the back of the iMac enough to keep it from getting hot, drawing heat away. If you have to run the mac at all, at least do that. Otherwise you will see your mac shut down on you.
You can force the fans to be always on or off. You toggle this behavior by:
- Shutdown Mac and unplug power for 5 seconds.
- Hold the power button down while you plug the power back in the Mac.
- Release the power. Now hit the power button again and you should hear your fans at 70%.
That's all folks.