Heat problem
 

FORD FREESTAR 2004, 135000 miles
Last time I had some problem with the front heater. I got the thermostat changed and the heater core. Last week, the heater motor gave up. I had it changed. Everything worked fine until yesterday. Heat and fan were at the maximum. Then I felt a cool breeze. The fan lost some of its power and maximum heat was barely warm. I turned down the heat to minimum and it went cold. I turned it back up. It only gave me barely warm. There is no loss of coolant.

Can this be linked together?
Can it be the resistor?
Thanks

Not sure.
The resistor only affects blower motor speeds as selected by the operator.
Considering how much work you had done , it could be there is air trapped in the system.
If you can, look for the 2 hoses that bring hot coolant to the heater core. Are both of them getting hot after the engine runs a while? They should both be hot, if not, what do they show? If they differ greatly temp wise, usually trapped air can do this .Sometimes, eventually, the air can get forced out and normal function resumes otherwise the air needs to be removed by either refilling the cooling system using a certain procedure or sometimes we will remove the upper heater hose just far enough off the heater core tubing to allow the trapped air to escape.
If both hoses are hot to the touch then there could be a problem with one of the duct doors not opening or closing fully. Let us know what you find.

The heat came back an hour ago. It's warm when idling and gets warmer when driving.
I haven't checked the hoses now. I'll do that tomorrow.