Heat won't turn on...cold only

[Robdaparamedic]

I have a 2000 Windstar, heat won't come on. First A/C only, now it won't switch to get any heat.

[tripletdaddy]

I'm really annoyed that I'm typing this up for the second time, as my computer locked up!?!

Basically there are two things that control if you are getting heat. Primarily, if the heater core isn't getting hot antifreeze, then everything else is secondary. Either you have a plugged heater loop or air trapped in it. One way to check for this is to grasp the two heater hoses that go through the firewall and see if they are hot and equally hot. You should also check inside behind the center console to see if the black air handler box is hot as antifreeze flows through it all the time.

If all that is good, then we move on to the secondary cause of no heat. Is the hvac only blowing through the defrost? If a vacuum line is leaking, the hvac will default to defrost if so. You may have a stuck or brocken air temperature blend door or motor/actuator, which is controlled by the temp control. The manual temp knob will rotated a potentiometer which will in turn send a signal to the actuator/motor to move the door accordingly. The digital button controls, I believe electronically generate the signal. It is common with Fords the actuator motor will brake it's internal gear teeth causing it to get stuck, not allowing any heat. Often they will make a telltale thumping or bumping sound when the hottest or coldest setting is selcted. Lastely, there are other blend doors involved that are are controlled using the engine vacuum. When changing the airflow direction/functions, you should hear the actuators move and the door maybe move and thump when it completely closes. It may be necessary to run the engine for a few minutes to buildup vacuum and then turn it off and then put the key in Run to be quiet enough to hear all the parts operate. Any hissing sounds inside or outside means there is a leak and maybe causing your problem.

[garync1]

Now do you hear clicking when you try to change the temp setting.?? Could be blend door motor. Not hard to replace and around 50.00 bucks or less.. If you do hear clicking it because the plastic gears on the blend door motor have worn and it wont allow the heat to come on and if last time set to heat may not let the AC come on. Mine a few years back was reverse. It was getting hot and my AC did not wont to blow cold. It was stuck in hot mode..

[Robdaparamedic]

I'm not hearing anything when I move the temp controls. Where is the blend door control motor ?? I'm getting heat through the heater core tubes. thanks.

Rob

[garync1]

Originally Posted by Robdaparamedic

I'm not hearing anything when I move the temp controls. Where is the blend door control motor ?? I'm getting heat through the heater core tubes. thanks.

Rob

http://community.webshots.com/album/556939487VdTPOV
The blend door starts on the last part of the first page and goes in the second page to best ways to get to it are by removing the stereo and pulling the glove box down all the way. You dont have to remove the glove box just push in by the stops and drop it all the way down.. As far as removing the stereo you will need to use a removal tool like in the pictures,you can get them from Advanced auto. Some have used coat hangers bet to look like the tool but I had some problems trying to use them.. Tool is 5.00 though.

[Robdaparamedic]

OK, just to clearify one thing. I have heat in the back of the van, just not up front. If the door wasn't working, wouldn't I not have heat in the back ??
I also have speedometer issues, all of a sudden. It is reading half of the speed and odometer miles, than it should. I will try the speed sensor.
Thanks for the help.

Rob

[CoachKarl]

Vaccum is what swings the doors around to send air from the condensor vs the heater core to your dash vents. Vaccum leaks can be tracked down best with your ear. Do you hear any high pitched whistling? (Under the hood? Under the dash?) It will change pitch when you pull on the throttle. The vaccum tubes are very skinny and brightly colored. They usually fail where there is rubber junction between two or several tubes . . . .

[Robdaparamedic]

Thanks, I'm working some serious hours this week and won't be able to look at it until the 4th. Thanks and I will keep you posted.

Rob

[truckbro]

Symptoms like this are usually indicative of a broken blend door. I found a kit that repairs the broken blend door problem with no dash removal and takes about an hour. The kit is called the HeaterTreater and they have installation videos on youtube. check it out: www.heatertreater.net