1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

"Hall" sensors

Discussion in 'Transmission & Drive train' started by Vigilante, Feb 8, 2015.

  1. Vigilante

    Vigilante Full Access Members

    Posts:
    87
    Likes Received:
    10
    Joined:
    Sep 30, 2011
    Location:
    San Francisco, CA
    So I have a constantly flashing 4 x 4 light on my dash. This research I have done points to "hall" sensors. I have no idea what these are. I replaced my speed sensor on the rear differential and that has made no change. What sensors are on the transfer case that can be replaced? Without looking, my research online has indicated that there is only a shift motor on the transfer case and no sensors. I have yet to change the speed sensor on the transmission. What and where are the sensors that can be replaced?
     
  2. Bedrck47

    Bedrck47 Full Access Members

    Posts:
    5,641
    Likes Received:
    630
    Joined:
    Jul 4, 2014
    Location:
    Elizebethtown, PA
    It helps to know what year you are talking about and any other information about your expy
     
  3. Vigilante

    Vigilante Full Access Members

    Posts:
    87
    Likes Received:
    10
    Joined:
    Sep 30, 2011
    Location:
    San Francisco, CA
    1999, 4x4, 4.6
     
  4. Vigilante

    Vigilante Full Access Members

    Posts:
    87
    Likes Received:
    10
    Joined:
    Sep 30, 2011
    Location:
    San Francisco, CA
    Any thoughts?

    I still have no leads on what anybody is talking about as far as "hall" sensors go.
     
  5. Bedrck47

    Bedrck47 Full Access Members

    Posts:
    5,641
    Likes Received:
    630
    Joined:
    Jul 4, 2014
    Location:
    Elizebethtown, PA
    These are the speed sensor that are on the transfer case

    see attached print mainly 34-03

    Send me a PM with your e-mail address and I will send you some information on how to replace them
     

    Attached Files:

  6. Steve Ruddy

    Steve Ruddy New Member

    Age:
    57
    Posts:
    1
    Likes Received:
    0
    Joined:
    Dec 1, 2017
    Location:
    Gerton NC
    My A4WD light blinks, but the 4X4 L or H does not blink, a few years ago I replaced the speed sensor on the rear transfer case because it would not engage without there being loud noises, replacing it stopped the noises and seemed to work but the A4WD light has always blinked, can anyone help me? 1998 Expedition XLT 4x4 - 4.6 V8
     
  7. Todd Campbell

    Todd Campbell New Member

    Age:
    62
    Posts:
    1
    Likes Received:
    0
    Joined:
    Dec 29, 2020
    Location:
    Saint Thomas, Pennsylvania
    Sounds like you need to replace the forward input speed sensor. 1997 to 1999, Borg Warner 4406 TOD (Torque on demand) transfer case. Can shift up to 70% of the drive line torque to the front wheels in A4WD mode. Hall effect sensor on the input shaft and output shaft. 1997 also had the VSS in the transfer case. If the transfer case will go in 4x4H when stopped, steady light, but blinks if you select 4x4 when moving 40 mph or more, one of these sensors is bad. If you select A4WD when stopped and the light is steady, but as soon as you exceed 30 to 40 mph it blinks same thing.
     
    Last edited: Dec 30, 2020
  8. Don Hall

    Don Hall Full Access Members

    Age:
    88
    Posts:
    461
    Likes Received:
    131
    Joined:
    Jun 8, 2018
    Location:
    SANTA CRUZ, CA
    FIVE YEAR-OLD THREAD?
     
  9. joethefordguy

    joethefordguy Full Access Members

    Posts:
    706
    Likes Received:
    206
    Joined:
    Apr 10, 2017
    Location:
    Texas
    https://en.wikipedia.org/wiki/Hall-effect_sensor

    A Hall-effect sensor (or simply Hall sensor) is a device to measure the magnitude of a magnetic field. Its output voltage is directly proportional to the magnetic field strength through it. The sensor type is named after the American physicist Edwin Hall.[1]

    Hall-effect sensors are used for proximity sensing, positioning, speed detection, and current sensing applications.[2]

    Frequently, a Hall sensor is combined with threshold detection, so that it acts as and is called a switch. Commonly seen in industrial applications such as the pictured pneumatic cylinder, they are also used in consumer equipment; for example, some computer printers use them to detect missing paper and open covers. They can also be used in computer keyboards, an application that requires ultra-high reliability. Another use of a Hall sensor is in the creation of MIDI organ pedal-boards, where the movement of a "key" on the pedal-board is translated as an on/off switch by Hall sensors.

    Hall sensors are commonly used to time the speed of wheels and shafts, such as for internal combustion engine ignition timing, tachometers and anti-lock braking systems. They are used in brushless DC electric motors to detect the position of the permanent magnet. In the pictured wheel with two equally spaced magnets, the voltage from the sensor peaks twice for each revolution. This arrangement is commonly used to regulate the speed of disk drives.
     

Share This Page