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EATC PROBLEM

(1999 Ford Expedition)
in Shreveport, LA on December 03, 2010
THE CLIMATE CONTROL IN THE DASH WONT BLOW HEAT OR COOL AIR.
HOWEVER THE CONTROL IN THE REAR OF THE CABIN DOES, BUT COOL AIR ONLY. IVE HAD THE THERMOSTAT REPLACED, BUT IT DIDN'T FIX THE PROBLEM.
Displaying 2 answers & 14 comments
Popular Answer
on December 03, 2010
Sounds like an air flow issue - like the motor that controls air flow door direction is not working.

Or - does it blow any air whatsoever in the front? Could be a blower motor issue if not.
on December 04, 2010
It only blows a little when it on vent setting. not heat or cool on regular or maximum
setting. could it be a blower motor problem even though the rear is blowing cold air only. i've had the thermostat replace but that didn't help correct the problem.
on December 04, 2010
Does the front fan sound loud? Or does it not sound like any air is blowing at all?

I am nearly certain it is an air flow problem, just trying to determine if we're looking at blower motor, resistor, wiring, vacuum, electric blend door issue...
on December 06, 2010
there are no loud sounds coming from the front, in fact i don't hear anything. I have had issues with the heat before, antifreeze was leaking onto the front passenger side. that's been at least 1-2 yrs ago if not longer. the fuses have been checked but nothing electrical or vacuum or this blend door, has been checked. Could it be the EACT SYSTEM all together needing to be replaced
on December 06, 2010
The EATC system doesn't have much to it - the control head, the blower speed controller, temperature sensors.
Since you have now cleared up that you do not hear the front blower come on at all essentially, the blower speed controller is classically the problem. This should be located on the firewall by the heater hoses.
on December 25, 2010
I sat in the truck a couple of days ago and actually heard the doors opening and closing.My truck year "1999" doesn't have a resistor. A friend actually took out the dash & center console, needlessly.The blower motor control module was actually more behind the glove box. There is the front panel, then the blower motor control module then the blower motor.He replaced bmc module to the tune of $137. which didn't fix the problem.He hot wired the blower motor, trouble shouting & it came right on.The only thing left is to replace is the front control panel itself, I guess? Can you think of anything else we can try to correct the problem of no heat ?
on December 25, 2010
Blower speed controller, as I mentioned. This is under the hood. It is the item I suggested on the last post. Sorry you are still having troubles.
on January 02, 2011
I really appreciate all your help so far. I can't seem to find any help in finding out where this blower speed controller is located. no diagrams to help find the exact location. the blower motor still not coming on. HELP !!!!
on January 02, 2011
OK, just refreshed my memory on the shop manual. You have already replaced the blower motor speed controller. It is slightly different on this vehicle compared to other Ford EATC units. My apologies on that front.

There IS a blower motor relay, on the same relay block as the flashers. It is on the left side of the center stack, under the dash. You could in fact have a bad relay!
on January 03, 2011
Would it be possible to get a diagram of the EATC that's specific for my year model truck. My email is divapj@gmail.com. Or could you point me in the right direction for any manual that deals with my trucks differences. We did check the fuse box to the left of the steering column and under the hood. All were looking good so far with those. Just need to locate your last suggestion. Hopefully that would solve the problem. Again thanks so much for your help.
on January 03, 2011
Sent...see if it helps.
on January 05, 2011
we have checked all the fuses and relays. Replaced the relay for the speed control module. A new finding there's no fire coming form the blower motor speed control module. It was replaced with a genuine ford product, had to order it. why do you think there's no fire coming from it going to the blower motor. We've hot wired the blower motor so it's not the problem. I hope I'm not getting on your nerves but my truck is all I have for transportation. I really can't afford to have ford repair it. Again thanks for all your help.!!!
on January 05, 2011
So, you saw the information I sent, yes? That's really all there is to the circuit and the system operation.

From the shop manual symptom chart:
For no blower operation, the following are possible causes:

Circuitry short/open.
A/C blower motor.
A/C blower motor speed control.
Blower motor relay.

You've replaced the blower motor, the speed control, and the blower motor relay. The only possible remaining thing is a wiring concern. Double check all your wiring connectors to see that they aren't burnt and have no terminal issues. This is a high power circuit, so melting is common.
on January 25, 2011
So I am sorry to hijack this thread but I am at my wits end. I have a 99 Expedition (Eddie Bauer) that the front blower doesnt work in. I dont have the Resistor as I have a EATC system so I have the 'fan controller' box that is mounted in the fender well of the passenger side kind of up on side of glove box. Does anyone know what thi part is called and where I can get it? It has two plugs one that goes I assume to the controller in the dash and the other to I assume the Blower motor itself. Please if you have any ideas email me at Chris @ TourPros . net Thanks !!!
on January 26, 2011
Blower Speed Controller. Ford Dealer part...
on July 12, 2016
I have a 1999 expedition, for about 2 yrs, air only blows cold when on max, shuts down only blows warm on other settings. Now this week only blows for defrost vent no other settings work.. but back a/c never an issue always blows cold ???? What are my options
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