Engine fan coming on periodically

Discussion in 'Trucks [ Eighteen Wheelers ]' started by CbarM, Oct 7, 2013.

  1. CbarM

    CbarM Heavy Load Member

    894
    247
    Jan 17, 2011
    Irvine, AB
    0
    Hey guys, '98 FLD120 w/ 6TS 3406E. A/C and defrost are NOT on. Engine has been at a constant 180-185 all day but the fan will kick on n then shut off 15 seconds later. What could it be? It started doin it last night n was normal before that.
     
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  3. biofumes

    biofumes Light Load Member

    201
    95
    Feb 13, 2009
    California
    0
    Had a similar issue, bypassed the wiring, and had it fixed. I'm sure you will have everyone ask you to replace the wiring harness.
    Seems to be a common issue, if it doesn't, sounds like it will be time to look into ecm. This was just my experience.
     
  4. manasteel

    manasteel Light Load Member

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    32
    Sep 10, 2012
    0
    4 things control the engine fan.
    1. fan override switch.
    2. coolant temp sensor.
    3. a/c hi pressure switch.
    4. intake manifold temp sensor.
     
    deming807 Thanks this.
  5. CbarM

    CbarM Heavy Load Member

    894
    247
    Jan 17, 2011
    Irvine, AB
    0
    Could the intake temp sensor also make it run rough at times when taking off?? Its been doing that also from time to time and getting worse as the days go by.
     
  6. westtndriver

    westtndriver Bobtail Member

    15
    6
    Jan 1, 2010
    West TN
    0
    I am having the exact same issue with my 07 c-15 acert, fan comes on for no reason,and just about every time especially in the morning when taking off the motor runs very rough while accelerating.... I have been trying to diagnose this problem for months.. Have also noticed more black smoke than usual on occasion while running rough in the mornings..I almost believe it could be something to do with the ecm...
     
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