97 vision heater problem

I have a 1997 vision. Today I noticed that when I start my car in the morning to let it warm up for a few minutes (it's cold here) the heater only blows cold air even when the temp guage reaches it's normal heat range (in the middle). As soon as I start to drive it, it starts to blow warm air like it's supposed to. Why would it work perfect when its (the car) moving, but when it's just sitting there it doesn't?

Your thermostat might be sticking or there is blockage in your heater core. I'd replace the thermostat first because it's the cheapest do it yourself fix.
Joe

Thank you for the info, but I figured it out and that was not the problem. Believe it or not, it was just low on antifreeze. I don't know why I didn't check that in the first place :dunno: ! Anyway it works great now!