Cooling fan issues

Discussion in 'Peterbilt Forum' started by Mustangjoey, Apr 2, 2019.

  1. Mustangjoey

    Mustangjoey Bobtail Member

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    Jun 29, 2011
    Rockford, IL
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    Before everyone jumps on my case and tells me to do a search, I have searched quite a bit and tried many of the suggestions.

    The truck is a 98 Pete 379 with an N14 Cummins. I bought the truck used and it has always had the engine fan light on in the dash and as soon as the truck has enough air the engine fan stays on at ALL TIMES.

    I have replaced the fan clutch solenoid, done the paper clip truck on the ac switch, etc. I am at a point that I’m not sure where to look next. The clutch is not froze up because when I disconnect the ground for my fan clutch solenoid the fan actually disengages. So what am I missing? What could be telling the solenoid to continue running at all times?

    Any help appreciated.
     
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  3. x1Heavy

    x1Heavy Road Train Member

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    Ask yourself "What's hot" where is that solenoid to go "Ouch" and switch fan on?
     
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  4. Mustangjoey

    Mustangjoey Bobtail Member

    36
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    Jun 29, 2011
    Rockford, IL
    0
    Not sure I follow. Faulty switch? I assume when the light in the dash is on, that’s because the fan switch is on. But I’m not an expert.
     
  5. HoneyBadger67

    HoneyBadger67 Road Train Member

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    Savannah, TN
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    St00pid question, but do you have a bunk override switch on the dash? Is it active? If so, is the bunk AC on? My wife has a habit of accidentally hitting the heat/cool switch and I always know because the engine fan will come on.
     
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  6. Mustangjoey

    Mustangjoey Bobtail Member

    36
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    Jun 29, 2011
    Rockford, IL
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    Not a stupid question at all. But it’s a daycab. Lol. No bunk switches here.
     
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  7. spsauerland

    spsauerland Road Train Member

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    West Harrison, In
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    Did you check the fuse? It is in fuse panel by clutch pedal. Don't think it is labeled very well.
     
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  8. Mustangjoey

    Mustangjoey Bobtail Member

    36
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    Jun 29, 2011
    Rockford, IL
    0
    I have looked in the fuse box. Didn’t see anything labeled for the cooling fan or switches. But I can take another good look!
     
  9. spsauerland

    spsauerland Road Train Member

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    West Harrison, In
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    It might be missing!
     
  10. Deere hunter

    Deere hunter Road Train Member

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    Shallowater Texas
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    I had the same thing happen on my 379 it’s a 2000 with a 2WS.
    I had to replace the wiring harness that goes from the ECM all the way to the front of the motor cured it.
    took me months to find it drove me crazy !!!
    Hope this helps
     
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  11. Omega1

    Omega1 Heavy Load Member

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    Nov 18, 2017
    Oregon
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    I"m having a similar issue with a 2019 T680. Going to KW tomorrow. I'm told that my most likely issue is the sensor located in the bottom of the coolant reservior. I realize its a different age and engine..just sharing.
     
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