Hate to be gravedigging such an old post, but I've just had the same problem with my '05 Impala. It's not the radiator fans, it's the heater and A/C fan, aka the "blower motor". I researched this online and found that it seems to happen after going through a cold car wash, which is what I did. That being said, anybody find a solution? It's about 15 degrees outside, and getting colder every day, and I hate having to drive my car until it warms up, pull over, pop in the fuse for the motor, drive to my destination, then pull the fuse after shutting my car off. Any help would be greatly appreciated!