An audible alarm sounds but all the fans in the fan cage (between drives and motherboard) are spinning.
On 4U enclosures
A pulsating tone plus a red light on the front panel.
On 5U enclosures
A continuous solid tone and / or pulsating tone with or without a red light on the front panel.
Using a replacement cable, bypass the card edge connector on the fan module and connect the fan directly to the backplane.
Download the attached PDF and following the instructions. The instruction is specifically for the 4U enclosures, but the same idea applies for the 5U.
Addendum to section 3
Before attaching the new cables to the backplane, first remove the original cables.