The car is a Taurus Wagon. It does not put out any heat. It is a flapper door issue. I tried changing the blend door actuator as the old one did not move when the temperature was changed from cold to hot. Unfortunately the NEW one doesn’t either, nor does it move when left hanging, not in the dash. It is an automatic temperature control unit. When I had the actuator out from under the dash, I could move the blend doors easily with the little lever, and get excellent heat, so I know it’s not a heater core issue. Everything on the dash unit, which includes the stereo/radio controls and buttons to shift the air from floor to defrost seems to work fine. It shows the desired temp, but won’t go to it. I have checked two fuses that are supposed to feed the HVAC system. I have even installed a different dash unit from another Taurus to see if it made any difference. That included a second temperature sensor, the “Y” shaped thing near where the white hose connects to the back side of dash unit.
I admit, I’m lost. I don’t have a good wiring diagram, and don’t know if I could read it well enough if I did.
Is there a relay or something in the system between the controller and the actuator that I don’t know about?
Which wire or wires in the multi-pin connector that plugs into the blend door actuator are supposed to be hot at what point?
Have you tried running the self-diagnostics; as skimpy as they may be?
Thanks @ok4450. My next problem is not knowing what an NGS tester is.
The Remote Climate Control module is what controls the blend door.
It’s the thing in the dash with all the HVAC controls.
@Tester Are you speaking of the center dash unit with the radio and all? I put another in place of the of the original, but it was a salvage unit of unknown quality. All the lights and variable temperature display worked on both of them. I suppose I might try a third.
I believe you have an electric motor that actually operates the valve that controls how much of the engines coolant will flow thru the heater core. By moving the adjustment with your hand you proved out that the valve can actually flow coolant and shut it off… What you have not proven out is whether the electric motor under your dash is able to move the same lever that you moved on the coolant valve. These motors do burn out from time to time. You may want to visit a salvage yard to get yourself another motor to control that valve.
I am deliberately focusing on the motor because the alternative is that your electronic control module is not working…and this is EXPENSIVE. You can obtain both the motor and the electronic control module from the salvage yard…albeit with no guarantee that they are any better than the ones that you have. Me personally I would try to get these parts from the yard…I have a U Pull IT type of salvage yard near me that has gotten my vehicles thru many years of use. If it wasnt for this yard I would have gone broke long ago…and I wouldnt have been able to repair and sell as many vehicles as I have over the years.
See if you can get your electric motor to operate under the control of your dash…
Your issue is either the motor has failed…or your control module has failed. Both are rather pricey to buy new…this is why i mentioned the salvage yard to you…I have seen people Junk their Taurus’s because of the high cost of these components believe it or not.
Try to get your motor operational…or get one from the yard and see if it works before you install it. I have repaired 3-4 of these systems in the Ford Taurus over the years…luckily for me it turned out to be the motors that control the heater valve.
There is no heater control valve on the Taurus.
The heat entering the passenger cabin is controlled with the blend door.
You can go to Rock Auto, and they list a blend door, a blend door actuator, but no heater control valve.
I’ve been repairing the HVAC systems on Taurus vehicles since they first came out. And they’ve never had a heater control valve.
Tester, you are definitely right about the lack of a coolant control valve. The blend door actuator doesn’t move, even when it is left hanging from its wires.
How about my question about your meaning of "Remote Climate Control Module?
ok4450, I still don’t know what an NGS tester is.
That’s what Ford calls the HVAC controller on the dash.
A New Generation Star tester is a Ford specific scanner the dealers use for HVAC diagnostics.
Not something you can buy from a parts store. Unless they special order it.
I guess I’m out of luck on the NGS. I wonder if a good Snappy scanner could find it. I don’t have one, but have a friend who does.
You can leave blend door in hot position? So your problem is not lack of heat, it’s adjusting it from hot/cool?
Call your friend and ask if they have the key for Ford HVAC diagnostics.
I’ll see him in the morning. He owes me some money, more than a diagnosis is worth.
@Cavell, yes, sort of, but temps vary widely during the day. The blend door falls to the cold position with the actuator removed. It could be taped in any position, but that’s not a “fix”.
Does the actuator appear to be moving? Can you see it without taking the dash apart? Maybe it is just the actuator has come undone from the door for some reason.
My pin-head guess is the actuator is kaput.
Have you used your multimeter and verified that the actuator motor is even getting the signal to move?
The point about the link is that a basic diagnosis could be done by pushing a few buttons on the EATC unit with no expenditure other than a few minutes time. The EATC does not have a memory function.
The various versions of the Star tester up through the NGS and IDS gets into real serious money so those are not options for the DIYer who may seldom use them.
As db4690 suggests, you might use a multimeter and check for a signal. As a further note, most of those EATC units may look exactly alike but there are dozens of variants and the incorrect unit could possibly be a cause of a problem.
@GeorgeSanJose No, neither the new nor old actuator move, even when hanging from the wires independently from the flapper door hole. After testing the old one, I bought the new one.
@db4690 Can you tell me which of the five (I think) pins should be hot at what point?
@ok4450 Good point about the different EATCs. The part numbers are slightly different being from different years, '01 & '04. I had read the EATC self test incorrectly, thinking that I needed the NGS. It said I only needed the NGS if I wanted to detect vehicle speed or coolant temperature. Duh… My mother, who retired from teaching many years ago, called that wishful reading.
Well, what I would do is play around a bit until I find the one that only has power when you’re asking the door to move
I recently had to diagnose a Ford truck actuator door problem, without a wiring diagram. And after a few minutes of playing around, I was able to determine which wire served what function
Speculating here MG, but the actuators are often stepper motors. The way they work is there’s an array of magnets and coils inside. When current is delivered to certain coils, in certain directions, the shaft will spin so the magnets align with the energized coil’s magnetic field. And stay there. It’s like if you have two bar magnets, they’ll rotate if you bring them close enough so that the north pole of one faces the south pole of the other. There’s only one shaft orientation that happens.
To get it to step forward, a different set of coils is energized, or maybe the same coils, but with a different direction of current to switch north and south. You can see how that could make the shaft rotate in increments. Step, step, step, etc etc. I expect that is why there are so many pins going to your actuator, one for each coil end, plus maybe one more for ground.
If so, it might be difficult to tell if the proper signals are being applied. Sometimes the computer that outputs these signals gets confused what orientation the motor shaft is actually in, so there is usually some kind of “homing” method provided in the manufacturer’s scan tool so the computer and the stepper motor align and agree on which orientation the shaft is at. One thing is certain, when it is supposed to be moving, if this speculation is correct for your case, there has to be voltages applied between some of the pins. You might just have to probe around to find which pins is all.
I recently took apart a laser printer for its parts, and one of the coolest of the parts it coughed up was a sizeable stepper motor. That one has 5 wires going to it too. Even with it disconnected, when you twist the shaft you can clearly feel the detent positions. It doesn’t twist smoothly in other words, but a step at a time. I presume that’s so when it is electronically stepped to a certain position, it will stay there. I’m not sure how those detents work though, mechanical, or magnetic.