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Mystery white/red wires, near aircon compressor

Discussion in 'Mondial' started by jelliott, Jun 5, 2020.

  1. jelliott

    jelliott Rookie

    Mar 8, 2010
    21
    Seattle, USA
    Full Name:
    Joe Elliott
    Title is hopefully pretty self-explanatory. In the course of changing the timing belts on my recently-acquired Mondial 3.2, I discovered the aforementioned pair of wires (terminated in female terminals in a shared plastic connector) dangling near the air conditioning compressor and branching from the same bundle as the wire to the compressor clutch. I flipped through the wiring diagrams and didn't see any "BR" wires passing through the C4 connector (which is where the compressor clutch wire comes from), so I'm stumped. Is my car missing a pressure switch or that's supposed to be on the compressor outlet or something? (Besides the air conditioning, I'm pretty sure the rear defogger is the only thing on my car that doesn't work, so it's hard to imagine what might be disconnected, unless there's some sensor for the fuel injection system that the car do without and no show obvious symptoms.)

    Thanks,
    Joe
     
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  3. FerrariJB

    FerrariJB Karting

    Jun 8, 2019
    62
    Netherlands
    Full Name:
    FerrariJB
    On my car the red and white cable is for the oildipstick / oillevel sensor. Mondial QV 82.
     
  4. Wade

    Wade Three Time F1 World Champ
    Rossa Subscribed Owner

    Mar 31, 2006
    32,194
    East Central, FL
    Full Name:
    Wade O.
    What year? US, Euro, etc? "rear defogger" meaning rear window defroster? In other words a Coupe, not Cab. Photo of the wires in question?
     
  5. mike32

    mike32 F1 Rookie

    May 13, 2016
    3,187
    Uk
    Drawing shows these wires as white with red stripe going to the engine dip stick via connector C4
     
  6. jelliott

    jelliott Rookie

    Mar 8, 2010
    21
    Seattle, USA
    Full Name:
    Joe Elliott
    Well, sure enough, there it is on the wiring diagram, two small-gauge "BR" wires passing through connector C4 and going to the oil level sensor. Not sure how I missed that. Thanks!

    Next potentially-silly question: Where is this sensor? Is it supposed to be integrated with the dipstick? Is that why these wires are in the vicinity of the AC compressor?

    Car is an '86 USA-spec Coupe.

    Thanks again,
    Joe
     
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  8. jelliott

    jelliott Rookie

    Mar 8, 2010
    21
    Seattle, USA
    Full Name:
    Joe Elliott
    Nevermind, there it is in the owner's manual; sensor is integrated with the dipstick.

    Next next question: Is this sensor just a switch that closes in response to low oil level? Is that why I'm not getting a warning light from the disconnected wires?

    Thanks again!
     
  9. Wade

    Wade Three Time F1 World Champ
    Rossa Subscribed Owner

    Mar 31, 2006
    32,194
    East Central, FL
    Full Name:
    Wade O.
    Replacement dipsticks are pretty expensive and its electrical connector gets broken as well. So it's not uncommon to find that the sensing circuit has been disabled in the past. Do you have a steady red or yellow warning light in the Check Control Panel? Any red LEDs lit for the engine oil?
     
  10. FerrariJB

    FerrariJB Karting

    Jun 8, 2019
    62
    Netherlands
    Full Name:
    FerrariJB
    Normally when you disconnect the sensor wiring you get the red warning light. My defect sensor I overruled it with a 12 ohm resistant between the red en white cable. Then the system thinks “oillevel ok, green light”.
     
  11. FerrariJB

    FerrariJB Karting

    Jun 8, 2019
    62
    Netherlands
    Full Name:
    FerrariJB
    If you do that: check your oil level often enough because the sensor is not working!!
     
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  13. jelliott

    jelliott Rookie

    Mar 8, 2010
    21
    Seattle, USA
    Full Name:
    Joe Elliott
    Nope; nothing illuminated for oil with the sensor disconnected. I’ve got the yellow master caution in conjunction with ‘Service Due,’ but no reds.
    (I would tell you how it behaves with the sensor plugged back in, but I’m in the middle of an oil change and decided to go ahead and replace the oil pan gasket, so there’s no oil in engine right now.)
     

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