I bought a Sunbeam multi-fan port
to use with my 120mm fans so they aren't running off the MB (except for my CPU fan). My rear case fan was originally plugged into this header on my P35-DS4 (Rev2.1) board.
I unplugged the fan and used a Rosewill 12" fan extension cable
to run the rear case fan to the Sunbeam, and I also plugged my front case fan into it. I then plugged one of my PCP&C Silencer 610's IDE molex plugs to the power connector.
The problem came when I turned the computer on; a loud continuous whine came from the case. Also, when I pressed the On button on the front of the case the computer clicked on, but then went right back off and then turned on again. I made it to the desktop without any other issues. I could see my CPU fan was running and the front case fan, but the rear fan was not.
I turned the computer off, plugged the rear case fan back into the SYS_FAN1 header, left the molex IDE plugged into the multi-port along with the front case fan, and turned the computer back on. The computer booted immediately without making any noises and without doing that weird off/on thing, and the rear fan started running.
I'm stumped as to what happened. I'd like to have the rear case fan plugged into the multi-port as well as any other fans I might get so if anyone could give me some suggestions I would sure appreciate it.