My car heater only seems to work when the car is in motion. It is nearly impossible to get the car defrosted in the early, cold mornings. I have checked the anti-freeze. I drive an 03 Mitsubishi Eclipse RS. Does anyone have any ideas on what the problem could be and how much it would cost to get it fixed?

 

Sounds like a simple thermostat issue. That is only like $5 and take all of 5-10 minutes to replace. If that don't work, then you might need a coolant flush.