Turned on the heat in the truck this morning and no heat. The blower will change speeds but I can't get the other controls to work like the direction for defrost and upper and lower vents also the air conditioning and my heated mirrors will not work. It's stuck on the upper vent direction. I was able to try another control unit and did the same thing. I checked all the fuses. Is there some other control or relay that might of gone to cause this? Where might be the location?

thanks