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Discussion Starter #1
Good Afternoon.
I think I may have a problem but not sure of the source. I have a 2009 Passion and the AC normally blows real cold. But lately I can be running down the road and the AC is blowing nice and cold and it will seem to start blowing warmer and warmer. I'll slide the control all the way up to hot and then back down and it will start blowing colder again. Where do I start looking for the problem?
Low Freon?
Bad sensor?

Please provide direction. I'm in South Carolina and it is warm.
Thanks.

Brad Dadles
 

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I'd make 2 guesses, either the evaporator is freezing up, (if the air seems to blow less) and is kicking out the compressor, or it is low on refrigerant. I would guess it might be the refrigerant being it is a 2008..It will tend to leak out when it isn't being used in the colder months.
 

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You might also want to check the thermistor that measures air temp. Check the connector is clean and tight.

:)
 

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Don't these cars have an electrically operated air blender flap? If so, I expect that is the culprit.
 

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They don't hold that much refrigerant and if it is low a bit, it makes a big difference. I added to my old 2009 each year and it got real cold after it was completely full. a few ounces makes a big change.

Not that hard to put a set of gauges on and see what the pressures are at.
 

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Discussion Starter #8
Is the heater flap or the air blender flap something I can get to easily?? Better yet where do I look for it and is it something I can clean or lube or is it a replacement part. Sorry for my ignorance but I'm trying to learn.


Brad
 

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There's no heat/cool flap shown in the alldatadiy.com info. There is a "recirculate" flap that closes off outside air but that appears to be it. Temp control is through the A/C control unit and it gets info on the air temp from the thermistor shown above. :)
 

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Good Afternoon.
I think I may have a problem but not sure of the source. I have a 2009 Passion and the AC normally blows real cold. But lately I can be running down the road and the AC is blowing nice and cold and it will seem to start blowing warmer and warmer. I'll slide the control all the way up to hot and then back down and it will start blowing colder again. Where do I start looking for the problem?
Low Freon?
Bad sensor?

Please provide direction. I'm in South Carolina and it is warm.
Thanks.

Brad Dadles
Everybody is guessing. Your clue is the fact that when you move the temperature control to hot and back to cold it will then start cooling again. That would not be the case if the refrigerant was low. If the refrigerant was low it not cool properly all the time.

The potentiometer in the hvac control can get fussy if left in the same position for a long time. Moving the temperature control up and down restores contact and the system works properly for awhile. The hvac control unit would need to be replaced to correct the problem. The part number for the hvac control has been superseded many times so it has apparently been updated. I had the same problem you describe and replaced the one in my 2009 with one from a later model year and have not had the problem since.
 

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Is the heater air blender flap not thermostatically operated? Usually when actual degrees appear on a heater control, the blender door is electronic. In any case - assuming it is - if VALEO made this system (which it probably did), the failure is not surprising. Could be the heater flap stepper motor or the electronic control unit.
 

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Before I replaced the hvac controls, or tore down the car to look at the blend door, I would have the refrigerant checked. Freon is a generic name for it back when cars used R-12, but now they use R134A (I believe) Probably would be best to take it to someone who knows the ins and outs of charging the system as overcharging it can cause just as much (if not more) damage.
 

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Before I replaced the hvac controls, or tore down the car to look at the blend door, I would have the refrigerant checked. Freon is a generic name for it back when cars used R-12, but now they use R134A (I believe) Probably would be best to take it to someone who knows the ins and outs of charging the system as overcharging it can cause just as much (if not more) damage.
If the air from the vents goes warmer and the suction line coming from the evaporator case is ice cold it is not a refrigerant problem. Work smart, not hard.
 
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