No Heat

I took it in to a mechanic. They tried replacing the thermostat but that did nothing. They checked the actuator but it was fine. They flushed the heater core again. All of the dials to control heat and fan speed were also fine. The car is not overheating at all but it is still only blowing out cold air.

They suggested to replace an auxiliary pump(water pump?) But that was all the mechanic could come up with. Could it be the water pump, even if it is not leaking?
Thank-you

When I warm it up it blows no heat slowly heats up to red on temp gage fans kick in temp goes down fans off temp goes up. Still no heat. When you drive it temp is fine and you start to get heat

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.

I had this problem and had to replace the thermostat cost me $34.00 all fixed! I love this site, the guides are great!

I have a 2003 Buick Rendezvous, The heater fans worked all day yesturday. After work I went to start my vehicle and the blower fans no longer worked. I checked the fuses and none were bad. What could this mean?

Heater problem
2003 Buick Rendezvous Engine Size unknown All Wheel Drive Automatic 76000 miles

My heater only works when hitting the gas and only when on one setting. When I pick the setting that blows the heat from the dash board directly at you, it works, when I pick the floor heater or defrost, it just blows cold air. I know nothing about cars. Would like some insight before heading to a garage. Thanks.

Heater problem
2002 Buick Rendezvous All Wheel Drive Automatic 86000 miles

Not all the time, but 90% of the time, my heater blows cold air when it is set on high.
My blower is strong, my car is running for more than 30 minutes, but it's still cold air.
I have also noticed that when my heater is blowing cold air, my engine thermometer is to the 3/4 mark some of the times.
If I need to replace the heater thermostat, how do I find/do that?

UPDATE! Several hours after I posted this message, my car "overheated" within 3 miles of leaving work. All my fluids were full, clean and after I let the car sit for 30 minutes, I was able to drive it home all while the temperature gauge fluctuated rapidly from cool to hot.
The shop found that both gaskets on my intake manifold were leaking. This is a common problem in this year of GM engines and they won't do anything about it even though they are very aware.
One of the leaking gaskets was very close to my temperature gauge and as the coolant shot out sparatically, this would cause my temperature gauge to fluctuate from hot to cold, causing my car to think it was overheating. If you have a GM engine model ranging from 2000 to 2004, check for these major problems.

I have the same issue, how do you check the Blend Door motors?

The car drives for all of ten minutes then overheats. There is no heat inside the car. I changed the thermostat, added coolant and did the bleeding things. What could be the problem?

Will resetting or pulling the heating fuse for sixty seconds help the overheating problem too?

Will resetting or pulling the heating fuse for 60seconds help the overheating problem too?

2002 Buick Rendezvous CXL over heated. I broke down a couple months ago from bearings in AC compressor going bad. The mechanic somehow fixed it with keeping same compressor in but ever since he fixed it, there's no heat. Sometimes it will blow warm air but then stops soon after and blows cold air. Have also noticed temp rises to over half when we start it and let it warm up for about 30 min. Today I let it warm up even longer hoping to have some heat, but when I got in to leave, temp gauge was all the way up and over heating. Not sure if it's just a coincidence but never had any of these problems until the mechanic somehow fixed the old AC compressor. Please help.