I have a 95 tahoe that the blower speed only works on high. I already replaced the blower motor relay, and that didn't change anything. I was told if it was the blower, would not work on any speed. If the problem was the blower motor resistor, the blower would not work on any speed. I believe at this point, I have to change the control unit. Anyone who has had this problem and figured it out? Appreciate all the info.