I have a 2009 model and the air conditioner is blowing hot air, the compressor is running and i can put my hand on the low pressure freon line under the bonnet just in front of the passenger seat and the line is very cold. This indicates that the AC system itself is operating well but there must be a flapper valve (or something similar) in the air ducting that direct airflow either over the AC coil or over the heater coil. Seems like my car isn't changing the air flow to go over the AC coil. Is it a fuse, a control unit, the devise that actuates the valve? i am at a loss where to even start looking. can anyone here help with some troubleshooting?
air conditioner issue
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The first thing I would do is make sure the thermistor that senses the temperature in the evaporator box is plugged in. Sometimes the connector gets knocked loose. I would disconnect and then reconnect the connector. It is located in the passenger footwell just to the center of the flat hidden shelf. I would also try moving the temperature selector up and down as well as turning the rotary knob with the blower on to make sure that air is being directed to all of the right places. I would also make sure that the front fan is coming on when the A/C compressor is engaged. If none of this works, you will probably need to have the HVAC system scanned to see if the controller is functioning as it should.
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You can get a freon recharge kit (not actual freon but the eco-friendly alternative they use now) at Walmart, Target, any major auto store and "juice up" your system.
usually around $30
I've done it to my 2008 twice (every few years)
Usually solves the problem.
usually around $30
I've done it to my 2008 twice (every few years)
Usually solves the problem.
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Be careful not to overcharge you AC. If too much R134 is put into the system, the pressure can go very high, triggering the blow-off valve and venting coolant to the atmosphere. If the pressure is just shy of venting, it can put excessive strain on the compressor causing failure.
If your a do-it-yourself type, I would recommend purchasing a manifold gauge set to set to avoid damage.
Just my 2 cents
If your a do-it-yourself type, I would recommend purchasing a manifold gauge set to set to avoid damage.
Just my 2 cents
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Sometimes the early cars lost the desired temperature setting. Work the temperature lever up and down a few times and see if it starts cooling.
You are correct that if the suction line is cold the system is full of refrigerant. That means the hvac control unit either thinks you want a warmer temperature or an internal air door or its actuator went stupid. I suspect the former. Costs nothing to try. If working the temperature lever corrects the problem then it is confirmed. The only permanent fix is to replace the hvac control unit.
You are correct that if the suction line is cold the system is full of refrigerant. That means the hvac control unit either thinks you want a warmer temperature or an internal air door or its actuator went stupid. I suspect the former. Costs nothing to try. If working the temperature lever corrects the problem then it is confirmed. The only permanent fix is to replace the hvac control unit.
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You can have thousands of reasons why this is happening. Most likely, some part is damaged, the main thing is that it was not a compressor, because when I had aircon not cold, I had a problem with the compressor, and I had to give enough money to replace it. It is best to turn to specialists. You will save yourself time and nerves, although you will have to pay cash, haha. I am such a person that I am ready to pay, as long as it is not particularly expensive but quickly. Well, that's why if I were you, I would give the car for inspection and they would tell you everything as it is. I'm telling you, maybe you will only need to pay money for cleaning the air conditioner, and this is a trifle.
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I'm having trouble with my air con, driver side vents is blowing very cold air but passage side is warm (like warm air from outside warm air) just been re-gased aircon pump kicking in.. I've moved temperature up to hot and hot air comes out all vents, but when moved back to cold problem still the same even moved dial to window/vents etc etc. Is there a flap that's not working properly? Or a sensor?
smart car 2010 mhd fortwo 451
smart car 2010 mhd fortwo 451
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1,585 Posts
It’s not a great idea to fill the R134 refrigerant without knowing how much you are putting into the system. Overfilling is often times worse than under filling - if there is too much R134, the liquid/gas cycle might be inefficient, resulting in inability to cool, the compressor work has too hard and premature failure.
Your best bet would be to have the refrigerant high and low pressures tested with an AC test manifold. Any competent AC service location should be able to do this.
That being said, the first thing to check is to see if he compressor clutch is engaging when the AC is turned on. You should be able to hear the clutch click and see the outer plate on the compressor spinning with the belt when the AC is turned on. If it’s not turning on, the system might “think” there is insufficient pressure and a check of the pressure switch would be the next place to look.
Next, definitely make sure your engine coolant is properly filled and there are no bubbles in the system. A bubble caught in the heater core can result in different temperatures from different vents. I worked on a vehicle a few years ago that blew hot air out of one vent and cold out of another. It turned out to be a clogged heater core. Hopefully that’s not the case with your Smart. In another case I worked on with hot and cold simultaneously, a replacement thermostat remedied the issue.
Another thing to check are the motor actuators for the blend and temper doors. They are mounted on the sides on the heater/AC body. If they get stuck, the temperature might not change or may change less than what’s being directed by the temperature control.
If you system has been exposed to ambient pressures, moisture can develop in the system that can affect the ability cool. If this happens, evacuating all of the refrigerant and extracting the moisture is done using a vacuum pump. In some cases, an internal desiccant, typically a cartridge inside the condenser, needs to be replaced.
The Smart also has a temperature sensor mounted above the passenger footwell. There have been cases when the wires to this sensor have been damaged or the sensor itself is faulty.
I hope this helps.
Your best bet would be to have the refrigerant high and low pressures tested with an AC test manifold. Any competent AC service location should be able to do this.
That being said, the first thing to check is to see if he compressor clutch is engaging when the AC is turned on. You should be able to hear the clutch click and see the outer plate on the compressor spinning with the belt when the AC is turned on. If it’s not turning on, the system might “think” there is insufficient pressure and a check of the pressure switch would be the next place to look.
Next, definitely make sure your engine coolant is properly filled and there are no bubbles in the system. A bubble caught in the heater core can result in different temperatures from different vents. I worked on a vehicle a few years ago that blew hot air out of one vent and cold out of another. It turned out to be a clogged heater core. Hopefully that’s not the case with your Smart. In another case I worked on with hot and cold simultaneously, a replacement thermostat remedied the issue.
Another thing to check are the motor actuators for the blend and temper doors. They are mounted on the sides on the heater/AC body. If they get stuck, the temperature might not change or may change less than what’s being directed by the temperature control.
If you system has been exposed to ambient pressures, moisture can develop in the system that can affect the ability cool. If this happens, evacuating all of the refrigerant and extracting the moisture is done using a vacuum pump. In some cases, an internal desiccant, typically a cartridge inside the condenser, needs to be replaced.
The Smart also has a temperature sensor mounted above the passenger footwell. There have been cases when the wires to this sensor have been damaged or the sensor itself is faulty.
I hope this helps.
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