I would like the fan to come on when I'm in traffic, and when I have my foot on the break the fan comes on, take foot off break and fan goes off but the fans still work as if it were still stock. I do a lot stop and go in traffic, I think this would be COOL. Is it possible.
Yes it would be possible by using a relay powered by the brake light switch that switches the fan relay ground. But the high speed fans on at idle is a major voltage drain as the alternator will not put out the ~60A needed with that load.
What I have found is a clean radiator and the fan turn on temp set to 206F works for me. The engine temp usually runs at about 190F on the highway, 200F in town. With the CC in an AC mode the high speed fans will be on anytime the car speed is below 35 mph.
There is a switch sold by Flex-I-lite part # FLX-31147 that will allow you to set the temp manually ad it would switch the fan relay ground to control them. This is what I used before I could program the fans to come on with the SCT software.
What reason do you want the cooling fans to come on? Is it for keeping the transmission cooler? Do you have a aux transmission cooler? I don't see any other reason for having the fans on unless they need to, it puts more drain on the battery, and makes the alternator work harder, wearing it out faster. If it's to keep the transmission cooler, they do sell a aux cooler that has it's own cooling fan, some of the SHO owners have them. If it seems like you car is running a bit hot, maybe it's time for a flush, or the radiator has scale build up. Those cooling fans draw a lot of power, almost as much as the rear defrosters do.