2000 astro van no frount heat

[rdb123]

I found a connection that is not pluged in It has 12 v when I turn the temp knob from heat to air . so I think that is why i have no heat . Does anyone know where it plugs into???? I have looked all over under the pass side dash? Thanks Roger

[MICHEALLEASE]

It's very likely a simple problem. There is a valve in the heater hose system that is vacuum operated. When the temp control is set to the maximum cold setting it closes this valve. This is designed to prevent hot coolant from going through the heater core, resulting in a more efficient A/C system. Let's say the entire summer you never used the heater. The valve was never opened. Now the internal spring that pushes the valve open when the vacuum is removed isn't strong enough to force the valve open. Locate the valve under the hood and manually move the lever back and forth. (The valve is located on the passenger side on the firewall just as the firewall bends to go along side the engine under the dash. Confused!?) Remove the rubber vaccuum line from the valve actuator. Does the valve remain closed? If the valve moves freely with no resistance, you need a new valve - problem solved. If you move the lever towards the vacuum connection and there is significant resistance and then returns to it's original position when you let go... you might have a vacuum leak. Start the engine and set the temperature setting to max cooling. Turn on the A/C. Now look at the valve. Is it open or closed? SHOULD be closed (lever is all the way toward the vacuum connector). When you turn the temp control UP, it will release the valve and open it. If you need to replace the valve it's only about $50 but it's kind of a pain in the Rumpus Majoris! I maintain about 40 Astros and this is a common problem in the fall. Good Luck! :-)

[candiver]

I have a 2005 Astro with front and back heat. I had the same problem, and had the cooling system flushed etc, but still had no heat in front, but lots in rear. The problem was in the vacuum operated heater valve located on the firewall, connected to the heater core. The little door which diverts the hot water had come loose from the valve, and was floating freely within the valve, blocking the hot water from entering the heater core. Replacing the heater valve assy did the trick. You can test this by removing the heater valve and bypassing the lines. If you get heat after bypassing the heater valve, you know that you've found the problem.

Have Fun!