Coolant level wiring

Discussion in 'Electrical' started by v8rumble, Feb 7, 2021.

  1. v8rumble Paid Member Paid Member

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    I have fitted the expansion bottle in the pic on an AUM swap.

    If I want to put an led warning light for low coolant can I just run an earth to and from the bottle contacts to the neg side of an led and a live to the other side of the led or is this expecting something to be easy lol

    coolant level.jpg
     
  2. H8V

    h8v Forum Member

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    I believe it's not as simple an arrangement as a float switch. I think it's just two contacts that are immersed in the coolant and the low level light is illuminated when the coolant level drops below the contacts. In that case there's only a very small signalling current and therfore a bit more electronics required to operate the light correctly.

    Why not rig up either a simple circuit with a battery and led, or just use a meter to try it, or alternatively poke your finger in and "see" what's inside?
     
  3. v8rumble Paid Member Paid Member

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    Thanks for the reply I will rig something up to see
     
  4. davidut5 Forum Member

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    My car did not have low coolant level warning, got a relay and some wires from a donor. It was not hard to fit, otherwise i would remember the operation.[:D]
    Relay fits in position 5 on ce2 and drives the red led in the clocks.
     
  5. H8V

    h8v Forum Member

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  6. v8rumble Paid Member Paid Member

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    Thanks for the info again:thumbup:
     
  7. rubjonny

    rubjonny Administrator Staff Member Admin

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    what fusebox/clocks do you have? CE1 the low coolant warning is handled by 42/43 relay, ce2 clocks its just wired straight to clocks.

    for the level sender when coolant level is ok, the circuit is closed circuit. so opposite to how you want it to work, easily adapted with a N/O relay
     
  8. v8rumble Paid Member Paid Member

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    Thanks for the reply.
    I have CE1 but no relay (easily sorted)
    I do not have any wiring present that I can find as poverty spec originally without a sender on the tank (rectangular bottle on the passenger side strut)
     
  9. rubjonny

    rubjonny Administrator Staff Member Admin

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    ok so if you want it factory grab relay holder and wire in 42/43 relay, if you want extra light then wire up a relay to flip the function if you get me

    42/43:
    S - to coolant level sender
    31 - earth
    15 - ignition live
    G - tap into coolant temp sensor wire, yellow/red from D/29

    earth 2nd pin pin level sender
     
  10. v8rumble Paid Member Paid Member

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    Thanks again will look at doing it that way:thumbup:
     
  11. davidut5 Forum Member

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    So i put the relay for nothing on my ce2 jetta Jon?
     
  12. rubjonny

    rubjonny Administrator Staff Member Admin

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    the 42/43 relay is only used on very early CE2 Jetta/Rallye which had CE1 cluster and Digifiz cluster, plus maybe some other VAG models in the range
     

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