this may just be a question for the cgminer thread ...but.
From what i understood, first you have to set --auto GPU & --Auto Fan, then you need to set a range for the Engine and Fan as a comma separated. Also you would need a temp target. This is all in the Read-me in the cgminer folder, have a look it is one powerfull ass program.
--auto-fan Automatically adjust all GPU fan speeds to maintain a target temperature
--auto-gpu Automatically adjust all GPU engine clock speeds to maintain a target temperature
"gpu-engine" : "900-1000,950-1000",
"gpu-fan" : "20-80,20-80",
"temp-target" : "70,70",
Adjust above to suit.
I mine with a temp target, and when a miner is first started it takes awhile for it to "settle" in at the temp requested . it does work great tho.