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BF75A Oil pressure switch light fault

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  • BF75A Oil pressure switch light fault


    I have just rigged my engine and found the warning light for the oil pressure does not light up.

    I have tested various parts of the circuit and I don't think this actually relates to bad oil pressure at all. The light does not come on when the ignition is on but engine not running, and I think it should be, so this would presumably rule out an actual pressure fault.

    I have found that inside the remote control box (R Type), there are 4 wires to the warning lights:

    Red (Temp signal?)
    Yellow (Oil pressure signal?)
    Black (earth)
    Black/Yellow, and Grey combined (12v+)

    If the yellow wire is disconnected then the oil light comes on with the ignition, but if I connect the wire then the light goes out.

    I have traced the wiring harness back to the engine and all the wires in the main harness have good continuity.

    The yellow wire terminates at the oil pressure sensor on the engine block, and appears to have continuity to earth when tested. I have a spare engine and the sensor on that behaves the same way.

    I think this is normal, so I would have to therefore assume that the yellow wire is the earth feed to the oil warning light and SHOULD have continuity to earth since the light is meant to remain on. So the fault is not the switch.

    So what do I need to look at? I can't think why connecting this would cause the light to go out, so any help in troubleshooting this would be much appreciated.

    Last edited by Cretster; 09-04-2012, 03:02 PM.

  • #2
    Actually - please don't worry about this thread - the problem is sorted now thanks anyway.