Coolant level sensor on a W900L

Discussion in 'Trucks [ Eighteen Wheelers ]' started by rockrawlin, Dec 13, 2008.

  1. rockrawlin

    rockrawlin Bobtail Member

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    I don't think mine is a 4 wire but can you tell me where they join the engine harness on yours?
     
  2. 550hpW900L

    550hpW900L Road Train Member

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    Mine is supposed to have one too but it doesent, yes the harnesses are the same but the wires that would be going to the sensor are most likely in the harness capped off.
     
  3. Jas

    Jas Medium Load Member

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    It joins the OEM harness on the top of the engine near the front tappet cover. If it doesn't have one you should be able to get a dealer to wire one up for you, its not hard, four wires, fit the sensor and the enable the parameter in the ecm.
     
    rockrawlin Thanks this.
  4. rockrawlin

    rockrawlin Bobtail Member

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    Thank you...I'll take a closer look at that harness in the morning. It's obvious that someone has been in there, just not sure what they did.

    The parameter is already enabled but it's not detecting the missing sensor so somehow the computer is getting back whatever signal tells it that the water level is ok.
     
  5. Jas

    Jas Medium Load Member

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    It sounds like someone has bridged out the wiring so the ecm thinks the levels ok. Maybe look for a wire loop on the harness that doesn't belong.
     
  6. rockrawlin

    rockrawlin Bobtail Member

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    Found it a few inches back into the harness. The connector was cut and the wires twisted together. It seems to me like that would throw a code but it didn't.

    Thanks again for the help, Jas.
     
  7. WallyGator

    WallyGator Medium Load Member

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    i have a 3406e and my sensor goes out at least 2 times a year.my fix was a paper clip just like the guy at cat told me to do.
     
  8. rockrawlin

    rockrawlin Bobtail Member

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    I'm not sure why your sensor keeps going out. I had one in 2 of my other trucks and never had a problem with either of them. I like the idea of having one because you can't always tell when you start to lose coolant. always seems to happen out in the middle of nowhere.

    With the last truck, it went off just as I was coming up to Willcox AZ. I was able to stop and get a hose before it overheated. I replaced a hose and was back on the road in less than an hour. It's better than sitting on the side of the road miles from nowhere.

    With this truck, it wasn't so obvious. It ran a little hotter than normal but never overheated. I had no idea I'd lost coolant until I shut down for the night and the apu wouldn't stay running for more than a minute or so. By then I was almost 5 gallons down.

    I put a new sensor in here Sunday and it starts beeping at me Sunday night. My original problem was a radiator cap getting weak. I replaced it and then sprung a leak on the apu. Again, I wouldn't have known about that without the low coolant sensor had I been driving any further than I did.
     
  9. Bigstretch

    Bigstretch Light Load Member

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    All of our Mack trucks have coolant sensors, and one of the T800 w/ a C12. But, the '03 T8 w/ ISX and my '04 W900L w/C15 doesn't have a coolant sensor.
     
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