Hello.  The system fans' speed is regulated by the DRAC/BMC. Attempt updating the BMC [URL] Else perform a soft  reset of the DRAC. 
I have a Poweredge 2900 that powers on and boots. But the fans come on full speed and the front LCD is amber with no text. It does complain about Remote Access Controller Initialization Failure. It boots up fine otherwise though.  I have tried updating the BIOS to 2.7.0 and disconnecting all power and removing the CMOS battery. But I still cannot clear the problem.  What can I do to fix it? Pictures here [URL]  [URL]  
Poweredge 2900 Fans full speed, amber LCD but no text