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  1. #1
    Shearwater is offline Registered User
    Location : Ampolla, a beautiful anchorage beside the delta of the R. Ebro 80 nm approx downhill from BCN.
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    Default wiring up an oil pressure gauge from scratch

    Having spent many a happy hour trying to get my VDO O/P gauge to function (!)....... I'd like to seek advice. So if you had a 12v supply, an o/p gauge and a sending thing screwed into the cylinder block, could you describe where to put the wires? Does a live wire go into the gauge at (+) come out at (-) then go to one terminal on the the sender, then go to ground from the other? Or does the 12v + go into the sender, then on to the gauge, then to gound? And why does the gauge have three terminals plus a self contained light unit?

    Sometimes outboards seem to have certain attractions!

    Thanks - yet again.

  2. #2
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    Anger is a wind which blows out the lamp of the mind.
    Robert Green Ingersoll

  3. #3
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    Quote Originally Posted by Shearwater View Post
    Does a live wire go into the gauge at (+) come out at (-) then go to one terminal on the the sender, then go to ground from the other? hhmmm, I'm going to say no here S_W. Or does the 12v + go into the sender, then on to the gauge, then to gound? not quite And why does the gauge have three terminals plus a self contained light unit?
    +12V, Negative, and sender input (G on your VDO guage?) Light unit for reading in the dark obviously, switched seperately via 12V supply (you got a instrument panel light switch? wire the light in here)

    Sometimes outboards seem to have certain attractions!

    Thanks - yet again.
    expanding a bit on F_C's post -
    to get the guage working, connect
    12V to "+" terminal (+12V from ignition switch "on" or take supply from an adjacent guage).
    negative to "-" terminal.
    sender to "G" terminal.

    If the sender is insulated return, as you have indicated above?, you need to bring a connection from "-" to the "I" terminal on the sender.

    that should do it.
    Last edited by cimo; 15-03-10 at 17:37.

  4. #4
    Shearwater is offline Registered User
    Location : Ampolla, a beautiful anchorage beside the delta of the R. Ebro 80 nm approx downhill from BCN.
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    Thank you both - I'm sure I can sort it now.

  5. #5
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    Senders/Gauges will generally work one of 2 ways.

    1. They will have a +12v and GND connection, so connect +12 to ignition live and gnd to earth (negative). Then there will be a separate connection for the sender which will be a single wire.

    2. They will have a +12v and GND connection only. Connect +12 to ignition live and gnd to the sender. The senders work by varying resistance through temperature or pressure, this alters the GND resistance and subsequently the voltage potential which makes the needle move.

    I think that's right anyway Please feel free to correct me.

  6. #6
    Shearwater is offline Registered User
    Location : Ampolla, a beautiful anchorage beside the delta of the R. Ebro 80 nm approx downhill from BCN.
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    My sender has two terminals so it looks like the diagram suggested by Full Circle might be appropriate.... but all tips are welcome as I can keep trying until one works.

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