2007 blower motor erratic

I have a 2007 Impala that has developed a problem with the blower motor. It will run normally for maybe 30 seconds or a minute, and then the speed drops down low for a few seconds and then returns to normal speed and repeats over and over. The blower motor rpms just drop to a low speed whenever it does this and doesn't stop completely unless you turn it off. I have read on here about older Impalas having problems with the blower motor relay. I believe the blower controls are computer controlled? Would this be the blower motor relay also, and if so, where is it located? Thanks for any assistance!