Apple Power Macintosh 8600 - Manual (Page 121)

5 If you disconnected the two connectors in step 2, reconnect them now.
IMPORTANT Make sure the two connectors are connected properly. Otherwise,
the fan may not receive power and the components in your computer could be
damaged due to excessive heat.
Speaker housing/card guide assembly
After you’ve reinstalled
the speaker housing/card
guide assembly, be sure
you reconnect these two
connectors to the main logic board.
121 Installing PCI Expansion Cards and Additional Memory