I have a 2002 impala 3800 that I've had to the dealer and they can't figure out what is wrong with my cooling fans. Sometimes everything works perfectly and others I only have high speed at 230* They replaced the ecm and nothing the same thing. Seems that if they work I can shut the car off and next time might not work. So , AC works perfect if fans are on when fans don't work AC quits unless I'm driving. I found conflicting info on the BCM. Some say it has nothing to do with fans and others that claim BCM could cause this intermittent fan failure.
When working properly, the low speed fans are on when ac is on, if AC is off they come on at 215* off at 210* only time high speed works is on at 230* and off at 225* when low speed fail to operate.
What is causing my issue? What do you suggest? First repair was $450 with no results.