My car heater only works when my car is moving, why?

I am not at all a car expert, not even a little. I am a girl who just happened to run into this same problem less than one week ago. I took it to the service station and $89.00 later they told me the problem was the car had no antifreeze left. So they topped it off, handed me a high bill, which comes with being a girl who knows nothing about cars, and now the heater works perfect, running and when it is in idol.

Maybe that's it. If it is you can check it yourself by looking right under the hood. Antifreeze, according to my bill costs $6.00. Save yourself the money and fill it yourself.

Good luck.

Maybe the fan is not working & it needs to be moving to circulate the air instead,Can you hear the fan running?

I think 73happn'd hit the nail right on the head. You need full coolant for proper heat.
A continuous flow without air pockets is one of THE most important things.
When's the last time you had a cooling system flush and pressure check?? Very easily neglected.
... and life73, you need to find where the missing coolant went. Water pumps and radiators sometimes only show up leaking when the engine is fully warmed up. That's a good place to start looking.
Good luck, you.

I have this exact problem. My water hose was replaced two weeks ago and my serpentine belt was changed two weeks before that. I do need to get the belt readjusted because it is squealing when I start up my car but I don't think I noticed the lack of heat until AFTER my water hose was replaced. At that time I had no coolant left - it was all over the road from where my old hose had separated. I'll check it in a few minutes when I go outside and will get back to you to let you know if that's the problem.