2000 ford taurus.I can only get warm air to cool air out of my heater.I replaced my water pump,thermostat,belt,and temp control,What else could it be.

Assuming the heater controls are ok there is a few possibilities.

The engine is being overcooled,
There is insufficient flow through the heater/the heater is partially blocked.
There is a permanent airlock in the heater/a failing head gasket is leaking an abnormal amount of combustion gas into the cooling system that is lodging in the heater and displacing coolant.

A partially blocked heater matrix is not unusual and is marked by seeming to have a good flow of hot coolant through it.

Normal flushing often doesn't shift the sort of sediment buildup that is common in a heater and high pressure air/water is often the only method that succeeds but it is a messy wet process that is very kill-or-cure - it is likely to destroy a weak heater matrix. The only alternative is to remove the heater matrix, dismantle it and rod the tubes through or simply replace it.

3.0L Engine

VIN S Engine

1. Before servicing the vehicle, refer to the precautions section.
2. Drain the cooling system.
3. Remove or disconnect the following:

• Splash shield
• Lower heater hose
• Radiator lower tube bolt
• Radiator upper front tube bolt
• Air cleaner assembly
• Battery and tray
• Water pump belt
• Upper radiator hose
• Engine vent hose
• Transaxle 10 pin connector
• Radiator bypass hose assembly
• Thermostat housing
• A/C compressor brace, if equipped
• Water pump mounting nuts
• Connector hose
• Water pump

To install:

1. Install or connect the following:

• Water pump
• Connector hose
• Water pump mounting nuts and tighten them to 15-22 ft. lbs. (20-30 Nm)
• A/C compressor brace, if equipped, and tighten the nuts to 15-22 ft. lbs. (20-30 Nm)
• Thermostat housing
• Radiator bypass hose assembly
• Transaxle 10 pin connector
• Engine vent hose
• Upper radiator hose
• Water pump belt
• Battery and tray
• Air cleaner assembly
• Radiator upper front tube bolt
• Radiator lower tube bolt
• Lower heater hose
• Splash shield

2. Fill the cooling system.
3. Start the engine and check for leaks.

Thermostat not opening fully

Water pump. First make sure you have enough coolant and the reservoir system isn't leaking(or any leaks). Fords are hard to get air out of the system. I always over fill Fords because of air. It will usually purge out in a couple days. only getting warm at idle and hot going down the road is a water pump or something is still clogged up. IE.. heater core.

Bob,there still may be air in there........I always bleed the air from the heater hose line entering the water pump. There should be a connection about a foot or so above where it enters there.
Take that loose while engine is cool.
Have someone start the car while you hold it downward AWAY from the alternator,and you stay clear also of that belt.
If the fluid gushes out of that line,it should be getting thru your heater core.
don-ohio

heater control valve shot

time to change water pump by passing or vortexting so to speak

Hello...

One of 3 things could cause this, that I know. The thermostat has been installed backwards. The water pump broke soon after install. Due to it being a rebuilt one. And a small clog in the heater core. All of these things are easy to fix.

Good Luck...

sounds like the controller went bad use temp checker see what your temp is at inlet of heater core from hose

If it's the 3.0L Vulcan Engine (OHV), the thermostat is on the driver's side of the vehicle. Follow the upper radiator hose back to a metal area with three 10mm bolts. This is the thermostat housing. Undo the bolts, and there's the thermostat. Mark the back of it with the old thermostat in it (if you get one with a jiggle valve, it'll make it easier to put the new one in because the jiggle valve needs to be on top). The thermostat and housing aren't perfectly round, so you'll have to play with it a little to get it to line up. Make sure to change the gasket. The spring side of the thermostat goes into the engine.

The water pump is in the serpentine assembly. It's the larger pulley located toward the firewall. It'll be easiest to remove the water pump if you also remove the coolant recovery tank. The water pump pulley has four 1/2" bolts that you need to take out WITH THE BELT STILL ATTACHED. I can't stress this enough. The belt will keep the pulley in place so that you can remove the bolts. Take the pulley off, then the belt. Remove the heater hose at the top and the radiator hose at the bottom. There are 12 bolts of two diameters (1/2" and 10mm if I'm not mistaken). Tap the heater hose lightly with a soft-faced mallet to break the seal with the gasket. Trash the old gasket. Replace gasket (you can also line the mating surface of the water pump with RTV Sealant, put the new gasket on the new pump, and line the other side of gasket with a second coat of RTV sealant if you want a really good seal). Install the water pump and torque to manufacturer's specs. Attach the pulley to the water pump hand tight and put the belt back on. Tighten the pulley bolts. Put the coolant recovery tank back in place. Fill with coolant, start engine, bleed and check for leaks.

To bleed cooling system: Idle the engine until the thermostat opens (you'll be able to tell bacause the upper radiator hose will be uber hot and you'll feel coolant running through this hose). Squeeze all hoses in the system that you can reach, but don't burn yourself. Stop the engine and let it cool. Open the radiator cap and squeeze the COLD upper radiator hose. You'll see some bubbles in your recovery tank. You might have to monitor your coolant level for a couple of days while the final bits of air are purged through your radiator cap (that's why it's pressurized).

Hope this helps. It's not hard, but it took me quite awhile.