02 EB Dual Climate ZERO heat | Ford Explorer Forums - Serious Explorations

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January 20, 2012
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Minneapolis, MN
City, State
Minneapolis, MN
Year, Model & Trim Level
2012 Explorer Limted
I am going to be breaking into the dash this weekend to identify if it is the blender door on the passenger side or the Heating core... before I get started I'd like to have parts on hand vs go seeking.

1.) what is the best way to identify if the issue is blender door vs heater core?
a.) How do you diagnose if it is a heater core issue?
There is NO heat in the vehicle at all

Background info: I randomly hear the clicking sound which appears to be somewhere high in the dash. I already replaced the driver's side blender door actuator 2 years ago. Dual Climate says it has an issue with the passenger blender door but nothing else when running it's diagnostic button pressing. I hear air moving, but nothing comes out of *ANY* vent for air movement. The status is same if I just start the vehicle or have it run for 15-20 minutes.

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Open the hood. Warm car. Feel lines into and out of heater core. If both are hot then You have flow.

Perfect, thank you Rocco123! Sometimes the simplest solution is so overlooked because of the situation being *considered* overwhelming in mind! Thanks, I will check when I am done with work. =D

I was rushed yesterday so I didn't get a chance and when I remembered it was late and all cooled down. So tonight for sure I'm checking the temperature but can someone riddle me this, if the orange is passenger floor air, green is the actuator for passenger side... if the white is not working, that could cause *NO* heat (or A/C) in the vehicle?


I checked the two aluminum pipes and they were not hot after a 15-minute drive. I am not sure if I was touching the proper item(s). Any insight if I was in the right area?



Yes those look like the heater core pipes and they should have been hot after a (very) few minutes running, unless the climate control is set to (colder, something other than heat) then the heater core valve should close. Follow those rubber hoses to see if there is a heater core valve, which could have a vac leak to it or have just failed. It should look something like the pic and link below.

You could detach the hoses and use weak compressed air blown into one heater core metal pipe to see if there is a heater core blockage. You could leave the hoses off and start the engine with HVAC set to hot to see if coolant is making it that far (but obviously would want a 2nd person helper to watch for it, tell you to shut engine off ASAP to not make a mess and lose a lot of coolant). If coolant is not making it that far you could pull the vac line off the heater core valve and feel for vac, and unplug the hose to the other end of the valve to confirm coolant is being pumped to it when the engine is running.


Referencing the picture of the exposed dash components (above) I did move the lever on the white vent and air started moving within the cab. Climate control is set to above 70 degrees so it should have been warm air, but it wasn't. I am glad to know that I could get a cable tie in there to leave that door open for movement of air period... now I'll check the valve and suggestions given by J_C regarding the valve and hoses for checking the heater core. (THANKS J_C for the directive).

Check that heater control valve as suggested above by JC. Pretty common issue for that valve to become inoperable in closed position. When closed it prevents hot coolant from circulating through the heater core. I've seen several threads in here with pictures and good directions I'm sure you will find by searching a bit.

Not sure why you are not getting air flow through any of the vents. Usually a complete loss of vacuum to the actuators results in defrost vents in open position. There is a plastic bulb called vacuum accumulator located under the dash on passenger side that can be kicked accidentally. You should have a look to see if the vacuum line has been knocked off the accumulator. That could explain the heater control valve too as it is also vacuum operated.

Have you checked to see if the recirculation door (aka fresh air door, flap, damper) has fallen down on top of the blower motor? That is immediately behind the glove box and visible through the plastic grating. If that happened it will really limit air flow from the blower.

Since you have all of the dash out, you can apply vacuum to each of those valves and make sure they actuate. The location where you have circled white also has a valve on opposite (drivers) side. Mine had a broken arm when I had a problem with no defrost.
Posted the repair of that valve on my youtube channel.
Did you end up having both heater lines very hot when running? Is coolant level good?

Just a thought. On my vehicle the heat only starts up after the engine gets to a certain temperature. After that point the fan starts and presumably the dampers operate. If this is the case, then the culprit could still be in the operation of the water valve. Shouldn't have an air lock unless the rad has been starved for fluid as in when the coolant is replaced. Since your heater lines are cold I would certainly suspect the valve or its' control. Not sure on the location but maybe a vacuum line could be temporarily connected to it to see if the lines get hot or not.