A/C vents on passenger side blowing hot while on cold setting

[jbwilli]

Mine wasn't blowing super hot air from one side. The temperature differential between the passenger and driver sides was very noticeable though. A new compressor solved the problem. I doubt there are any other issues with the heating and cooling system. It works completely normal. We don't know if the OP literally meant that "hot" air is blowing from the passenger side. If that is the case then I don't think it is the compressor.

The only way any air that is not COLD can enter your vents is for the blend doors block off the COLD air flow section and open up the ambient, warm or hot air flow section!

 

[94Eddie]

The only way any air that is not COLD can enter your vents is for the blend doors block off the COLD air flow section and open up the ambient, warm or hot air flow section!

Explain my situation then.

 

[jbwilli]

Explain my situation then.

First, I do not want to make an argument out of this at all. I am only trying to educate and help you.
(Note: I use CAPS to only emphasize a point, not to be loud!)

You may have described your original problem of the temperature vent flow of COLD air coming out of one side and WARM/HOT air coming out of the other side of your vents incorrectly (no big deal! )

...OR..

You can't seem to grasp the fact that your compressor only processes freon in your a/c system, which results in making the evaporator inside the pax compartment and behind your dash extremely COLD. That is the only thing it does..make that evaporator COLD. You also have a heater core under your dash. It is heated by the coolant in your engine/radiator system. The heater core gets warm to HOT. That is the only thing it does..make that heater core HOT!

This is where the blend doors come in! These blend doors do exactly that...blend the COLD and HOT air available FROM the COLD evaporator or the HOT heater core until it matches the temp you as the driver select. it can be 100% all COLD or 100% all HOT or anything in between! In addition they direct this air flow into the different vents in your Explorer...dash/floor/windshield defrost/etc.

Your Explorer has DUAL air! You can select different temps for driver and pax sides. You have left and right side blend doors! They are independently controlled by these blend door motors! These motors are controlled by the on board computer! There are many inputs (to many to list here), but their position can pull air flow from the COLD evaporator chamber OR the HOT heater core chamber INDEPENDENTLY to the left and right vents AND in A variable mix (Both COLD/HOT). THIS IS THE ONLY WAY THE TEMP CAN VARY FROM ONE SIDE TO THE OTHER)!

All the above said, I hope you know understand the new compressor (although needed) had nothing to do with correcting your perceived problem of one side pushing COLD and the other side pushing WARM/HOT!

My best guess is your dealer either 1) RESET the on board computer that controls the blend door positions, and/or 2) replaced another ac control part and/or 3) disturbed and inadvertently corrected a bad electrical or vacuum connection in the process!

I can assure you, I chased this same exact problem for over a year and it would come and go. It can be erratic. Mine was blend door motors that were out sync with the on board computer.

Again, I am only trying to educate and help you understand and not criticize you in any way!
Should your problem come back, feel free to contact me!
Are we OK now? I hope your issue is resolved.

picS below: How the compressor does it one and only job...make the evaporator COLD
and simple generic blend door system air flow (yours is way more complicated).

 

[94Eddie]

You haven't educated me. Tell me why replacing a weak compressor would fix an uneven temperature issue between the driver and passenger side vents. This happened whether you want to believe it or not. No other components were changed. I know the compressor was weak because I turned the clutch plate myself. The refrigerant level was fine and not contributing to the issue. All other parts of the vent system worked as designed and still does. I understand how an AC system works. I took plenty of physics, math, thermodynamics, chemistry etc. courses to get a BS in engineering.

I did not start this discussion with you. For some reason you seem to want to convince me that replacing a compressor did not fix an uneven temperature issue with my Mountaineer when it absolutely did. There isn't any underlying issue that was masked over with this repair. The other parts of the AC and heating systems have worked as designed before, and since, the repair was done 15 months ago. No other repairs have been done to it to date.

The suggestion to the OP to check the compressor has no downside. He checks it and finds the compressor is fine and crosses this item off his list. Or he finds it is weak and replaces it. I am not saying replacing the compressor will fix his issue but it did for me. There is no need for another post from you to convince me that something I experienced did not happen.

 

[jbwilli]

You haven't educated me. Tell me why replacing a weak compressor would fix an uneven temperature issue between the driver and passenger side vents. This happened whether you want to believe it or not. No other components were changed. I know the compressor was weak because I turned the clutch plate myself. The refrigerant level was fine and not contributing to the issue. All other parts of the vent system worked as designed and still does. I understand how an AC system works. I took plenty of physics, math, thermodynamics, chemistry etc. courses to get a BS in engineering.

I did not start this discussion with you. For some reason you seem to want to convince me that replacing a compressor did not fix an uneven temperature issue with my Mountaineer when it absolutely did. There isn't any underlying issue that was masked over with this repair. The other parts of the AC and heating systems have worked as designed before, and since, the repair was done 15 months ago. No other repairs have been done to it to date.

The suggestion to the OP to check the compressor has no downside. He checks it and finds the compressor is fine and crosses this item off his list. Or he finds it is weak and replaces it. I am not saying replacing the compressor will fix his issue but it did for me. There is no need for another post from you to convince me that something I experienced did not happen.

I sincerely was trying to help you. I apologize that you feel otherwise.
I know from your perspective it is difficult understand my explanation, and I understand your frustration.
DUAL AIR Explorer/Mountaineer HVAC is far more complicated than you can imagine.

I stand by statement, a bad or weak or new AC compressor has nothing to do with HOT air coming out of one vent and COLD the other, with AC on! Only a blend door malfunction can allow HOT air into the mix! Ask a Ford mechanic for confirmation!

This is my last comment on the matter.