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Engine fan on full and A/C not working

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Old May 11, 2026 | 04:48 AM
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Engine fan on full and A/C not working

2016 C250 AMG line
As the title states my cooling fan is on full permanently and A/C not working.
have read that it could be low a/c pressure, is it worth getting a/c pressure tested and re gassed first, never been done in my 8 years of ownership
anyone else have this issue or similar
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Old May 11, 2026 | 07:13 AM
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Originally Posted by Pezzar
2016 C250 AMG line
As the title states my cooling fan is on full permanently and A/C not working.
have read that it could be low a/c pressure, is it worth getting a/c pressure tested and re gassed first, never been done in my 8 years of ownership
anyone else have this issue or similar
Check refrigerant level.
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Old May 11, 2026 | 07:14 AM
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Check this sensor as well https://mbworld.org/forums/c-class-w...mely-loud.html
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Old May 12, 2026 | 02:06 PM
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From: MA Coast
W204 2010 C300 4matic Sport M272
Could be related or separate issues.

I would scan the car for any fault codes. I think everyone should have a vehicle specific OBD scanner. Can get a Launch Creader for $100-$150.

The ac was blowing hot air in my W204 last summer and with using the scanner I was able to diagnose the issue and in the end simply added 1/2 can of refrigerant to get it cold again. With the help of the scanner i was able to see how things were functioning, specifically I was able to see that the compressor was turning on, the refrigerant pressure was changing but remained low, and that the evap temp wasnt going down. I was able to add refrigerant and see the pressures going up and temp going down.

I wrote a thread on it here: https://mbworld.org/forums/mercedes-...ctions-do.html

Im sure you can fix the issue yourself without bringing it to a shop.
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Old May 19, 2026 | 10:45 AM
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Was the aircon pressure sensor.
my local specialist did the work, coat £370 all in
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Old May 19, 2026 | 12:21 PM
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Originally Posted by Pezzar
Was the aircon pressure sensor.
my local specialist did the work, coat £370 all in
What's the part number?
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Old May 21, 2026 | 03:17 AM
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W212 MY'14 M276-3.5NA @75kMi
High side pressure sensor is located on the condenser,
Harness connector subject to water penetration.
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