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Caterpillar 315c l a/c problem

Discussion in 'Excavators' started by truecountry, Jun 25, 2019.

  1. truecountry

    truecountry Senior Member

    Joined:
    Sep 25, 2007
    Messages:
    383
    Occupation:
    Shop Manager and Tech
    Location:
    clarksville va
    Guys I been working on this excavator for a week on a/c unit ..Serial # is Cjc01986
    Compressor was locked up replaced it and dryer and expansion valve ...
    Pulled a vacuum and a leak on hose ..from expansion valve to dryer
    Long story short compressor will not kick on unless I frame ground the blk 14 common wire to compressor
    Look at wiring diagram and trouble shooting their is a thermostatic switch that if stuck open will not let compressor kick on ..
    My question is where is this switch located at ? it shows a 20 amp and 15 amp fuse with it on wiring diagram but no part number listed
    Thanks Allen
     
  2. Bls repair

    Bls repair Senior Member

    Joined:
    Jan 21, 2017
    Messages:
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    Occupation:
    Equipment operator,mechanic
    Location:
    S E Pa
    Is there a high pressure and low pressure switch in the drawing?
     
  3. Theweldor

    Theweldor Senior Member

    Joined:
    Feb 17, 2018
    Messages:
    322
    Location:
    Western, NY
    A serial # would be most helpful to you and us!!!!!
     
  4. Cmark

    Cmark Senior Member

    Joined:
    Jan 2, 2009
    Messages:
    2,021
    Location:
    Australia
    What wiring diagram do you have? This is what it should be to the compressor. 200-black is always battery negative.

    comp.jpg
     
  5. John C.

    John C. Senior Member

    Joined:
    Jun 12, 2007
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    Occupation:
    Machinery & Equipment Appraiser
    Location:
    Northwest
    I have a code list for the AC units I think that are installed on that model. I'll have to do some digging to find the buttons to push on the AC control panel in the cab to bring up any fault codes. It might take me a bit so if anyone else has the right combination of buttons, feel free to post.
     

    Attached Files:

  6. Mobiltech

    Mobiltech Senior Member

    Joined:
    Jan 15, 2014
    Messages:
    971
    Occupation:
    Self employed Heavy duty mechanic
    Location:
    Sask.
    If you’re looking for the low temp cut off switch it will be in the evap core in the heater ac unit. It uses a capillary tube in the core to keep it from freezing.