360 AC Fuse Blowing?

Discussion in 'Technical Q&A' started by pbonaguro, Aug 5, 2018.

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  1. pbonaguro

    pbonaguro Rookie

    Sep 30, 2010
    14
    Tried to search around the forums and couldn't find any advice directly related. My 1999 360 Modena AC has been working fine all summer and just stopped working today. The 7.5A fuse behind the driver seat was blown and when replaced just blows again. The only thing I might still be able to do on my own is replace the AC relay which is also behind the driver seat. Any other thoughts?
     
  2. hessank

    hessank Formula Junior
    Rossa Subscribed

    Aug 8, 2005
    913
    Canada
    Full Name:
    Fred
    How's the compressor?
    Is it seizing and pulling too much juice?
    While keeping the fuse removed I would pay close attention while putting 12v directly to the compressor ONLY to establish if the clutch is frozen or sticking.
    But that's me. I cannot advise you to do that.
     
  3. pbonaguro

    pbonaguro Rookie

    Sep 30, 2010
    14
    Thanks for the reply.. every little bit helps. You bring up a good point that if the compressor is frozen for some reason, might draw more juice. I'm a decent mechanic working on my own cars, race cars, etc., but gonna tip toe into this one. I'm looking for a quick fix.. wishful thinking I know. Have ordered a new relay which is a cheap attempt at something simple.
     
  4. ferrarioldman

    ferrarioldman Formula 3
    Professional Ferrari Technician Silver Subscribed

    Jun 19, 2002
    1,001
    Summerfield, NC
    Full Name:
    Tom Jones
    I have had several of the compressor clutch coils go bad. Common problem. Joe at Polar Bear a/c in Florida can fix you up. www.polarbearinc.com/
     
  5. maurice70

    maurice70 F1 Rookie

    Jan 25, 2004
    3,884
    Sydney
    Full Name:
    maurice T
    If the compressor is seized it won’t draw more amps as it is belt driven and not electrically driven,,
    if the clutch coil has shorted out to ground,then that will blow a fuse..
    When you replaced the fuse,did the fuse blow whilst the car was running or did it blow with the key turned,dash lights on but engine not running?
     
  6. pbonaguro

    pbonaguro Rookie

    Sep 30, 2010
    14
    Thank you all for the info. I also received a diagnosis tip/reply to my email from Aldous Voice. Fuse doesn't blow with the car running and the AC stop button pressed in/engaged. As soon as you turn off the Stop button the fuse blows. So it would seem the problem is definitely at the compressor end. So I'm just going to remove compressor and have it rebuilt. Thanks again for your responses
     
  7. pbonaguro

    pbonaguro Rookie

    Sep 30, 2010
    14
    Did a little more work/test this evening. Without the car running and with a remote 12 volt battery, I tested the AC clutch and it worked.

    Then instead of the 7.5amp fuse, I put in a 15 amp fuse for about 15 seconds and the compressor engaged, ran and didn't blow a fuse.

    So any definitive thoughts on why the compressor is drawing more than 7.5amp standard fuse size will be appreciated. I'm assuming the answer is that I need a new clutch?

    Thank you.
     

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