Ok I have no heat whatsoever. Let Me tell you this first my car overheated and I had a hell of a time trying to figure it out I changed everything, radiator, temp switch, water pump, thermostat, hoses, flushed the entire system. Along with flushing the heater core. Anyways after doing all that the car was still overheating so I found out that the last thing was that it was a head gasket. I did not change this since the car is so old and miles are high. So I bought some blue devil gasket sealer. And flushed it like it says bam. Works no over heating. But their is no heat in the car only blowing cold air. Iv read about checking the heater door actuator, I see that on the drivers side the actuator is moving same with the passenger side is moving also. So I was thinking that it might not be that cause it seems to be ok. My blower motor is new also and is working fine. I read about a heater control valve I cannot find that or is their one on the buick rendezvous? I am totally stumped any ideas I would really help.