Why my heater isn't working?

I dont think your truck has a heater control valve. The radiator fluid should always flow thru your heater core in your car. The temperature is controlled by the temperature blend door. The situate the heater core and close the door over it allowing air to flow thru the evaporator and into the ducting. When you select heat, the door opens allowing some air to flow across the heater core and into the ducts. The more the door opens, the more air is directed across your heater core. This guide can help us fix it.

https://www.2carpros.com/articles/car-heater-not-working

If you are not getting warm air with full hot selected, it sounds like that door is not opening. Other possibilities are clogged heater core, bad electronic control going to the actuator for the temp door.
In looking at the electrical control circuit, it is very simple. There is a dedicated fuse for the Blend Door actuator in the junction box fuse/relay panel that delivers power to the actuator. It had a ground wire that goes to G200 ground. Three other wire go to the temp control switch. If you disconnect the plug to the hot/cold control knob, and jumper pin 1 and 2 together, that should drive the actuator to full warm. Short pin 2 to 3 will drive it full cold. Test it out and see if the motor will drive. If yes, replace the control switch. If not, check for power to the motor and a good ground. Powere and ground at the actuator, and still no movement. Replace actuator.
Good luckl.

I can't remember whether the f150 had an electric blend door actuator or a vaccum pod. I think it has an electric control for the door. You need to locate the blend door and figure out what it has. If it is vaccum, stick a vaccum pump on it and see if it moves the door. If it has an electric motor, you should be able to see the shaft turn when the temp is adjusted. Hope this helps you. Please post your results, even if you have already fixed it, as this info will help others in the future.

The A/C compressor kicking with the heater is normal on an automatic climate control system. It sounds like you have a temperature blend door actuator that needs replacing. You could have something stuck in the blend door and also check the vacuum supply to the actuators and control head. Check out the diagrams (below). Please let us know what happens.

Sounds like you have either a bad heater control valve, partially plugged heater core or the blend door in the HVAC unit is not moving like it should. The blend door is cable controlled from the knob. Do you feel any temperature change when you move the knob? If yes then I would lean more toward checking the coolant flow through the core. Do both heater hoses get hot? If one is ho and one cold the core may be plugged or the control valve (if it has one in the heater line) may be defective.

Nice work, we are here to help, please use 2CarPros anytime. Let us know if you need instruction on the thermostat replacement. Here is a general guide.

https://www.2carpros.com/articles/replace-thermostat

Cheers, Ken

Good to hear, please use 2CarPros anytime we are here to help.

Cheers, Ken

Hello,

This vans get the heater core air locked. Jack the rear of the van as high as you can safely and then start the car and open the radiator to fill the system the tilt of the van will release the air pocket on the core,

Here is a guide to help you

https://www.2carpros.com/articles/jack-up-and-lift-your-car-safely

This guide can help as well

https://www.2carpros.com/articles/car-heater-not-working

Please let us know if you need anything else to get the problem fixed.

Cheers, Ken

If there is no heater valve, the system must work from a "blend door" which is located near the heater core itself. It allows fresh air from the cowl to enter the vehicle, and based on how much heat you want, the blend door allows the air to pass over the core.

Check to make sure there are no cables or vacuum lines running to that area which are disconnected. Also, look for a vent door that appears to regulate the air passing over the heater core itself.

This guide shows the broken vacuum line problem with these trucks.

https://www.2carpros.com/articles/air-vents-stay-in-the-defrost-position

and

https://www.2carpros.com/articles/car-heater-not-working

Here it is for your car (below)

Please let us know what happens.

Cheers, Ken

Hello,

This does sound like an actuator problem. Here are a few guides that should help you run down the problem:

https://www.2carpros.com/articles/low-or-no-air-flow-from-vents

https://www.2carpros.com/articles/car-heater-not-working

Tell us what you find out.

Thanks,
Alex
2CarPros