Posted this over at the HVAC forum but thought I would try it here also. I have a 2001 F150 SCREW 4x4. Last winter the climate control (hot/cold) **** stopped switching between hot and cold.... it would only blow heat. I figured it was a broken blend door and decided to tackle the job this spring. Everything else works like it should.
Well, I have dug into it and the blend door is fine. The actuator motor appears fine also. I replaced the actuator motor and still nothing. I checked the voltage going to the motor and got NOTHING. So my question is, could it be the climate control temperature switch on the back of the climate control panel that is bad?
I have not checked the voltage going into the switch yet but I am at a loss right now. Could the actuator motor get power from somewhere else or does it come from the climate control switch?
Last edited by supernova1021; 05-17-2010 at 10:30 PM.
How did you test the blend door actuator as fine ?
Did you check the fuse to the blend door actuator motor ? This is CJB ( aka Central Junction Box / cab fuse panel ) Fuse # 5. This is the Light Blue w/ Pink stripe wire to the blend door actuator on connector C229. The ground for it is the black wire on the pin next to the Light Blue w/ Pink stripe wire. ( pin 7 & 8 ). This fuse is hot in the run position.
The blend door is actually stand alone from the blower part of the HVAC system, the power is supplied to the blend door actuator from CJB fuse #5, and the function selector switch is just a potentiometer, and depending on the resistance it provides to the blend door actuator solid state control, it operates the motor that moves the blend door.
Where did you check for power to the blend door actuator motor at ?
I replaced the motor with another that was working when removed that day. When it didn't work, I checked the voltage at the connector coming into the motor. No voltage.
I did check all fuses in the cab and all appeared fine. I just didn't know if the switch could have had anything to do with it because it looks like someone had previously messed with it since it had some pry marks on it.
Your post helped me out a bunch.. I will have more time to mess with it this weekend. At least I was able to turn the blend door to the cold position so I won't roast for the time being! I will definitely check that fuse good.
Last edited by supernova1021; 05-18-2010 at 09:14 AM.
Sscully, I had a few minutes tonight and checked the fuse panel again. F5 has voltage and fuse looks good. I see it also supplies power to other functions according to the owners manual and everything else is working fine.
I need to double check the voltage coming into the actuator this weekend. But I'm still stumped if it isn't a bad switch.
Ok Sscully, need your expertise. I DO have voltage to the actuator motor. I took the actuator apart again and watched as I plugged it's connector in. The motor runs and turns the gears as far one way as it can and then, of course, stops. Turning the climate control **** does nothing.
I replaced the actual motor with the replacement motor and it did the same thing. I went to the local salvage yard today and found another petitiometer (what I am referring to as the switch) and put it on the backside of the ****.... Still did nothing to control the motor. I'm lost as to what is wrong.
The Motor turned to a position, and then stopped or just hit the limit and kept trying to turn ?
Did you unplug the function selector switch and power the motor to see if it turned still ?
Thinking something is not right in the actuator itself, causing the motor to think it is continually being signaled to go to a position, and the potentiometer is jsut going along for the ride. If you look at the diagram above, you can see where the wires come into the actuator, there is a resistor in the circuit going to the solid state control for the motor.
The other place could be the solid state control, if this is not attached to the motor itself ( cannot recall right now if it is ).
The motor turns to it's limit only one way and stops. I did not try the motor with the function selector switch unplugged if you are talking about the vent, ac, heat, defrost, etc. switch. I did try it with the climate control (hot/cold) switch unplugged. And it did the same thing, did not make a difference..
Havent messed with it again, but according to the diagram you put up the solid state appears to be in the actuator housing on the board and not in the motor. And if that is the case it would explain why when I switched out motors, it would do the same thing as far as turning to its limit and stopping.
I'm just going to order a new actuator off line. They only run about 35 bucks and I now think that is the problem also. Thanks for your help. I'll keep you posted.
Any updates on this. I have exact same problem. Were you sucessful in getting it to work? My actuator will not turn at all. (I tested it before I dug into my blend door in case that may have been the issue). So now I don't think my blend door is the problem. While I am mechanically inclined I am no good with electrical.
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