you should map devices with --gpu-map; to do this run each card with

cgminer --scrypt -d 0

note which gpu's temp info is raising up and then increase -d 0 to -d 1 (and so on).

while doing this you can also use --gpu-fan 100,5,5,5,5 (if you have 5 gpus, if you have less or more change ,5 accordingly). This way you'll be 100% sure that the device 0,1,2... is the device you're going to target.

anyway, you'll have a map like 0:2,1:3...

use the map with --gpu-map 0:2,1:3 but still, if you want to be sure, use -d 0,1,2... to check whether the right card is now heating.

i believe that you know what to do afterwards.

cheers