Expansion Tank Coolant Sensor & Wiring Help | FerrariChat
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Expansion Tank Coolant Sensor & Wiring Help

Discussion in 'Technical Q&A' started by mike, Jan 12, 2006.

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  1. mike

    mike Formula Junior

    Nov 2, 2003
    721
    Colorado
    Full Name:
    Mike
    #1 mike, Jan 12, 2006
    Two things:
    First:
    I am replacing the coolant temp. sensor on my 86 328. There are two spade connectors that attach to the sensor. The wire colors are; one black wire, and the other is a violet striped black wire.
    The connectors on the sensor appear to be the same size in width, but I have not taken a mic to them yet.

    I am wondering if the wires need to be connected back on the sensor in any particular manner ie: are they polarity/ECU specific? If so how does one determine which one goes where since they appear to be the same size.

    Second:
    There is an electro-valve under the expansion tank/ left rear fender that connects to the cut off valve via a vacuum hose.
    The electro valve has two spade connectors that attach to it. The wire colors are; one pink wire, and one beige striped black wire.

    Currently the connectors on the electro valve are situated horizontally (with one toward the car body and one toward the engine). The electro valve connectors appear to be the same size also. The wires have been connected with the beige striped black toward the car body and the pink toward the engine.

    I think this is incorrect and was wondering if the manner in which these are connected matters also.

    I was looking at the wiring diagram and really didn't understand it since I'm unsure of the orientation. If I understand it correctly my wires are attached opposite the wiring diagram.

    So, does it matter which way these are connected? ie: pink toward car body or toward engine?
     
  2. spiderseeker

    spiderseeker Formula 3

    Jul 22, 2005
    1,718
    Colorado
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    Steve
    #2 spiderseeker, Jan 12, 2006
    Last edited by a moderator: Sep 7, 2017
    I'm sure there is an expert here that can verify what I'm going to say but
    polarity shouldn't matter on either one.
    I just finished changing the electrovalve (because of an open coil-s/b 45ohms or so) on my 308qv. and I checked the coolent temp sensor- the coolent temp sensor should show closed(near 0 ohms) when cold and open(infinite resist) when warm.
    The electrovalve gets 12v applied and operates the coil for the pulse injection system- since coils don't have polarity, it shouldn't matter(unless one lead is grounded and I don't think it is). Attached is a photo of mine in case you want to match up the wires(good idea) - NOT positive the 308qv and 328 systems are identical though.
    Steve
    Image Unavailable, Please Login
     
  3. mike

    mike Formula Junior

    Nov 2, 2003
    721
    Colorado
    Full Name:
    Mike
    #3 mike, Jan 12, 2006
    Steve,
    Your photo shows the same electro valve, except I don't have the bulbous (metal cut off valve) attached to mine. Basically we have the same set up but my cut off valve is isolated from the elecro valve.

    I am replacing the expansion tank sensor because I was getting ohm reading (cold) across the board. what do you mean open coil?

    So if I understand it doesn't matter which way the wires are connected to the electro valve or the expansion tank coolant temp. switch.
     
  4. spiderseeker

    spiderseeker Formula 3

    Jul 22, 2005
    1,718
    Colorado
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    Steve
    #4 spiderseeker, Jan 12, 2006
    Mike- for sure the wires don't matter on the coolent switch- it's just an off or on switch. It tells the ECU when the engine is cold or hot. The coolent switch should be closed (zero ohms when cold) and fully open when warm(infinite resistance).
    The electrovalve coil terminals should read about 45 ohms across them if it's good. Mine was open (infinite resistance, so I had to change it). Not positive about the wire polarity though, but pretty sure it doesn't matter.(just keep them the same as your original or just copy mine if your wires are loose)
    Steve
     
  5. mike

    mike Formula Junior

    Nov 2, 2003
    721
    Colorado
    Full Name:
    Mike
    #5 mike, Jan 12, 2006
    Steve you have a PM.

    Mike
     

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