6nz fan won't shut off

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by jriol94, Dec 3, 2020.

  1. jriol94

    jriol94 Bobtail Member

    17
    7
    Nov 14, 2020
    0
    Have a Peterbilt 379 2002 and fan won't shut off. Truck was a project and I just took it out to work and it won't go off. No ac system in the truck as of right now, don't know if that can cause it. I just changed the valve solenoid but I don't think that fixed it (haven't taken it out, did start it and was on). Noise is driving me crazy, if I can't get it fixed, is there any way I can just put it manually?

    TIA
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. Dave1837

    Dave1837 Road Train Member

    1,206
    3,732
    Nov 16, 2019
    Pennsylvania
    0
    Fan solenoid on the firewall, they go bad all the time. Should be in the center by the wiper motor
     
  4. pushbroom

    pushbroom Road Train Member

    1,740
    7,100
    Sep 1, 2012
    0
    The high pressure switch on the a/c system can turn the fan on as well. Use a paperclip to jump the pins. it needs to be a closed circuit for the fan to be off.
     
  5. jriol94

    jriol94 Bobtail Member

    17
    7
    Nov 14, 2020
    0
    Changed it yesterday. Fan still on, now leaks air when I shut the truck off from bottom of solenoid
     
  6. Dave1837

    Dave1837 Road Train Member

    1,206
    3,732
    Nov 16, 2019
    Pennsylvania
    0
    Does your truck have a PTO?
     
  7. jriol94

    jriol94 Bobtail Member

    17
    7
    Nov 14, 2020
    0
    It does
     
  8. Dave1837

    Dave1837 Road Train Member

    1,206
    3,732
    Nov 16, 2019
    Pennsylvania
    0
    I confused my PTO solenoid for my fan solenoid because they were basically side by side, not trying to say you're not mechanically inclined by any means but they looked identical lol another thing that made my fan run was being low on coolant and the AC system being over charged. I don't really have an answer haha just ideas
     
  9. jriol94

    jriol94 Bobtail Member

    17
    7
    Nov 14, 2020
    0
    I hear ya bro. Yeah I dont have a pto solenoid. Coolant is good and I have no ac system so that could be a reason I believe. Going to see if I could just switch it over to manual and call it a day
     
  10. jriol94

    jriol94 Bobtail Member

    17
    7
    Nov 14, 2020
    0
    Anyone know how to put the fan to only turn on manually? This thing is driving me crazy
     
    6wheeler Thanks this.
  11. pushbroom

    pushbroom Road Train Member

    1,740
    7,100
    Sep 1, 2012
    0
    Did you ever look into the a/c high pressure switch or bring it by a shop that can hook up to it? Ecm will say what switch/sensor is turning on the fan.
     
    spsauerland Thanks this.
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  • Draft saved Draft deleted