Yesterday Morning I got in the truck, started and heater warmed up quickly and all was good. Yesterday afternoon I get in to go to lunch and soon realize the air blowing from the vents isn't warming up! The engine gauges show normal operation....I switch from "Panel" to "Floor" and the same result....cool air even when the temp is full Heat. Strange thing...if I select "Max A/C"....I get warm air ...not hot, but warm.

Does this sound like the Blend Door....or some thing which controls the blend door?

I called the dealership and they said depending on problem...I'm looking at $600 to $700 to fix.

Any thoughts?

 

Mine had similar symptoms, and although the temp guage showed well within the normal range, thermostat wasn't working properly. Replaced it and now have lots of heat.

 

On a lot of the f150's the temp guage gets it's reading from the cylender head temp sensor and these do noy have a collent temperature sensor as such, so you can have near normal operating temp but you don't have hot enough coolent to make the heater work, thermastat is an eay install and well worth a try.

 

Thanks to both of you for your replys.

I've since noticed that it doesn't matter what position I have either the Temp Control or Air Flow in....I get the same cool/warm air flow.

I have a buddy whose an F150 guy going to take a look at it this weekend and then I'm dropping off at dealership Monday for the Cruise Control recall. Hopefully by Monday I'll have a real handle on the problem. Seriously hope it is just a Thermostat!

I'll let you all know the result

 

Let us know what you find. My 99 Expedition 5.4 just did the same thing today. No heat from the front although the rear heat works fine and temperature etc. all normal. Both heater hoses hot so it appears that the heater core is getting hot coolant; it just isn't getting blended with the fresh air.

My Haynes manual says to use the Electronic Automatic Temperature Control self-test, but I will wait until tomorrow to try it. It has two codes which I suspect might be the problem; blend door short and blend door failure.

Now, who here knows how to check those out?

-Todd

 

these trucks had a problem with the heater control ****. The **** cracks and then has a vacume leak so it does not change the temp setting.

 

Good News for me......my problem ended up being the Temp Control. Not the **** being cracked, but the actual unit itself. Replaced it in 10 minutes and everything is working fine now! I was lucky this time. Just super glad it wasn't the Blend Door!

Good Luck to the rest of you!

 

Unfortunately, mine is the blend door. Similar to other threads on here, once I checked the actuator and found it to be working, I removed it and pieces of plastic from the door fell out into my hand. Oh well, I guess I need to try to get a blend door at the dealer and go through the process of removing the dash etc. to get to it.

It sure looks like Ford could have used metal in this application instead of plastic!