Question : Problem: Powemac G5 Cooling Fan running full blast from startup.

I did a firmware reset on this powermac g5 to try to resolve a previous issue and ever since the fan comes on full speed until it is shut down.  Other than the fan things are just fine.

I am not running SETI or any CPU intensive background apps.  Yet the fan still runs only at one speed... too fast.

What do I need to do to reset the fan to normal variable speed operation.

Answer : Problem: Powemac G5 Cooling Fan running full blast from startup.

If you just updated to 10.4.3, I think there is a bug in 10.4.3 update...

1) Do a SMU reset as describe in http://docs.info.apple.com/article.html?artnum=300341

if it doesn't help,
2) Do a PRAM/NVRAM reset as describe in http://docs.info.apple.com/article.html?artnum=2238

if it doesn't help,
3) Open the Energy Saver System Preferences panel, and click the Options tab. Click the Processor Performance pop-up menu, and set it to either Highest or Lowest -- anything other than Automatic.