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A few times a week my air conditioner will start blowing room temperature air for 5-10 minutes before going back to cold. I mostly keep the AC set on Auto around 70. It will be blowing fine, then room temperature for a few minutes, then back to AC. Anyone have this problem before? I have tried to take it off of Auto, turn temp down, nothing.
Most likely the Heater Control Valve. They start failing and then you get these symptoms. Usually also means that the coolant has never been flushed and has gunk in it.
Part number is A2308300084
Its part 170 on the attached picture and it lives under the windshield wiper assembly.
Thank you all. I am not sure how to measure the pressure so I will have to take it in for that to get checked (while also mentioning it could be Heater Control valve and/or coolant issue). At least I have some idea of what it could be...hopefully its the most reasonable of the aforementioned suggestions.
2007 S600, 2007 Chrysler 300 SRT8, 2000 C5 Corvette, 2017 Mustang GT, 2023 300C, and a 2019 Lincoln
Not unusual for a heater control valve to go after 10 years. Not expensive to replace. Use an OEM part. We have heard of Chinese parts that reversed the on/off function of the valve. Keep us posted.
A few times a week my air conditioner will start blowing room temperature air for 5-10 minutes before going back to cold. I mostly keep the AC set on Auto around 70. It will be blowing fine, then room temperature for a few minutes, then back to AC. Anyone have this problem before? I have tried to take it off of Auto, turn temp down, nothing.
2013 S550 4matic
Any help is appreciated. Thank you
2013 S550 RWD here.
This can be the cabin temperature sensor issue. I have this problem. Temperature sensor sometimes reads way cooler than what the cabin temperature really is so it stops blowing cold air.
To check the system capability to produce cold air is simple. Set the temperature to LO. In this setting the system blows cold air regardless of the cabin temperature so if it does you don't have issues with refrigerant or control valve.
I use a iCarsoft MB II scanner to read sensor values and it is clear the issue in my car is bad temperature reading.
I have not fixed it as it is intermittent and does not happen too often and when it does I just set it to LO but one day I will fix it. It can be a simple bad wire connection too as it normally works just fine.
Sensor is the red dot on left side of your START button. If you put your finger on it you will get your fan run higher and cooler air as it reads your body temperature as cabin temperature.
Access to sensor is from the foot well and I guess it is quite easy to change if the sensor has gone bad. I plan first just to disconnect/reconnect the wire harness and see if it helps. I think it will, if not, I'll replace the sensor.
Also add to the list the temp sensor in OCP, similar to the one next to IGN.
Sometimes OCP quits posting temps and HVAC modules simply uses -30 default without posting a fault. So you really need to read the live data to check values are near your expected temps.
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