I made an account here just to post this because it came up when searching for a remedy for the problem..
**DO NOT ATTEMPT IF YOU DO NOT FEEL COMFORTABLE MESSING AROUND IN THERE! You can get a very nasty shock by not knowing what you're doing touching the wrong thing!
I have the exact same model exact same problem.. I have a small background in electronics so naturally I popped her open to see what I could do. This is the first time ever messing with one of these.
Turns out the fans were good. The thermostat circuit was what was broke. This circuit is a small PCB that is screwed onto the left big heat sink (with the PSU wire harness facing you and the AC plug on the back). I saw that it had a yellow wire supplying 12vdc running from the bottom board to it, its located on the bottom right corner of the PCB. Poked around with the voltmeter just to make sure.
All I did was solder the RED fan wires to that particular spot where the 12 volts comes into the PCB. You do not have to do anything with the BLACK wires.
To test outside a PC, short pins 15&16 with a piece of wire, plug in the AC, and turn on the switch. The fans should come on.
Now, this can wear your fans out a lil faster since now they aren't being throttled, but its better than not working at all!
Oh, and yes, I did make sure there wasn't a funky bios setting keeping the fans off.
Update: Definitely got sick of the noise of the fans on full blast so I threw in a potentiometer to make it adjustable.
Edited by Auto_Turret - 2/9/10 at 4:07pm