HVAC

[walkman50]

I have a 2010 Mountaineer with an automatic, dual zone system. The air coming out of the right side vent on the center stack is much hotter than the air coming from the driver's side vent. Does this sound like an under hood issue or an under dash issue? Or, could it relate to switches that may be part of the dual zone option?

 

[hibbbbbs]

Are both the zones set to the same temp? I'd imagine so, it could be the blend door for the right side not working. Does the air temp stay the same regardless of what it is set to? Is it just the right side center vent that's hot - what about the far right vent? That would help determine blend door vs something else.

 

[Explorer_PL]

Most likely you need YH1759 blend door actuator.

Very common.

Check the part number but it's under the dash. Tight space but doable with 7 or 8 mm ratchet wrench.

 

[Campnham]

could the actuator motor be bad without the "clicking" noise?? I'm developing the heat only out the right center vent problem myself. I'm ok with it. Wife, not so much!!

 

[walkman50]

Are both the zones set to the same temp? I'd imagine so, it could be the blend door for the right side not working. Does the air temp stay the same regardless of what it is set to? Is it just the right side center vent that's hot - what about the far right vent? That would help determine blend door vs something else.

If the air conditioning is off, the right side vent blows very warm air.Turning the air on and lowering the temp to 60 makes it more normal, but still warmer than a 60 degree setting should be.

 

[Explorer_PL]

Yes, the motor can be bad without clicking noise.

 

[hibbbbbs]

I would definitely take a look at the blend door actuator. You can fit your hand in there like PL suggested but I'd recommend not re-installing the top bolt that holds it in, the lower two hold it in perfectly fine for me.

I've also heard that the temp must be set to cold when replacing it, not sure if that's true for the dual zone model, but worth looking into. Before you buy a replacement you can open it up and see what's wrong. On the single zone models there's a little plastic gear that breaks and it prevents the connecting blend door gear from spinning. If a few of the teeth broke on yours that could be why you're not getting the full range of temps.

 

[walkman50]

Does the dual zone automatic system have two actuators?

 

[walkman50]

I finally replaced the right side actuator after obtaining an 8mm wrench that would loosen the last screw. Extremely tight area because of the wiring harness. One slight hiccup involved the arm that comes out of the part to engage the receptacle in the duct work. The cogs have to be in the same position as the defective part being removed. So, I had to power up the new part before installing it to adjust the arm cogs by raising and lowering the temp setting. This is not a repair that I ever want to do again. Anyone with large fingers will have more grief that I experienced.