How does A/C work?

Discussion in 'Electronics' started by Alex, Jul 10, 2017.

  1. Alex

    Alex Hardcore MB Enthusiast

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    In terms of CAN signals. Did MB ever publish this information? Trying to find out what controls the swashplate angle in the compressor.

    Long shot but you don't ask, you don't get.
     
  2. Diesel Benz

    Diesel Benz Hardcore MB Enthusiast

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    Front SAM likely. Which car are you talking about?
     
  3. OP
    OP
    Alex

    Alex Hardcore MB Enthusiast

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    The a/c has only one wire going into it and that's from the engine ECU. I want to find out what exactly is being transmitted so I could replicate the behaviour. The car is 2003 211.
     
  4. Diesel Benz

    Diesel Benz Hardcore MB Enthusiast

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    Sure? Which car are you talking about (exactly, please give us the VIN)? What is the part number of your engine ECU?
     
  5. OP
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    Alex

    Alex Hardcore MB Enthusiast

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    Positive. The car is 2003 E55. A1131533979 is the ECU p/n.
     
  6. Diesel Benz

    Diesel Benz Hardcore MB Enthusiast

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    Looks like your car is unique. This is how other W/S211 E55 AMG cars are built:
     

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  7. OP
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    Alex

    Alex Hardcore MB Enthusiast

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    My CL55 is unique too then. Both are early production cars and have identical single wire connection to the a/c.
     
  8. Diesel Benz

    Diesel Benz Hardcore MB Enthusiast

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    Single wire yes but on other cars this single wire goes to the front SAM, not to the engine ECU.

    Not a big deal though, all these control units share information and are aware of the AC compressor state etc.
     
  9. Vitobrabus

    Vitobrabus Active Member

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    In variable displacement compressors it's normally mechanical. As the suction pressure rises, so does the angle of the plate....this them pumps more refrigerant and lowers the suction pressure until it balances out.
     
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