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plow lowers my truck voltage

Discussion in 'Western Plows Discussion' started by tony0713, Dec 11, 2014.

  1. tony0713

    tony0713 Junior Member
    from pa
    Messages: 18

    when I connect my plow before I even use it, just even connecting the electrical plugs. my trucks volts drop to 12.3-12.8. when I'm using the plow it'll go to about 12. the truck is a 07 ford diesel with a new alternator and 2 newer megatron interstate batteries. the plow is a 08 pro plus ultra mount. without the plow on the truck it runs 13.9-14.1. a month ago I took all the connections apart on the plow and cleaned them.
     
    Last edited: Dec 11, 2014
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,967

    So, no lights on at all, and you plug all 3? Plugs in, walk back to the cab, and it's at 12v?
    You took EVERY connector apart? Sorry but I highly doubt this.
    While using the plow, 12v is normal.
     
  3. tony0713

    tony0713 Junior Member
    from pa
    Messages: 18

    all the external connections that were rusty
     
  4. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    I question your voltmeter, are you going by the OEM voltmeter in the dash? These are unreliable and inaccurate. Plugging the plow in draws so little power that your alternator SHOULD compensate without skipping a beat. The only power it's going to pull is a fraction of an amp to switch a relay in the isolation module to redirect your headlights (that aren't on apparently) and just a bit more to activate the back light in the controller. Your radio draws more power than that just to light up the display!

    Where are you main power cables for the plow connected? The positive is best put right on the battery post and the negative either also on the battery or on a real good spot right on the engine block. I often use a stud on the PS cylinder head right at the front near the fan. The farther down the line from the battery positve post you connect your plow + cable the more it will effect your vehicle system voltage because when you lift the plow it takes more current than your alt will put out so it draws a big chunk from the battery. But that is quickly replaced by the alt when you release your finger from the plow control.

    Get a real electrician's voltmeter and put it right on the battery then try again. Plugging in your plow with no lights or functions in use shouldn't even show a change.
     
  5. Antlerart06

    Antlerart06 PlowSite Veteran
    Messages: 3,437

    Check your grounds and clean them I have a Pro plus some reason Thats only plow I have clean the grounds every few years
     
  6. bmc1025

    bmc1025 Member
    Messages: 35

    Check your battery to body or engine to body grounds. Does the volt meter drop when you have the turn signals on or turn on headlights?
     
  7. tony0713

    tony0713 Junior Member
    from pa
    Messages: 18

    I have it wired right to the driver battery. both positive and negative.

    the volt meter I'm using is not the dash gauge but a multi gauge that plugs into the obd connector.
     
  8. tony0713

    tony0713 Junior Member
    from pa
    Messages: 18

    I already did. as i mentioned in the original post.
     
  9. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,967

    You never answered tho. As soon as you plug in the plow, the volts drop...No lights on the plow no nothing?
    What connections were rusty?
     
  10. tony0713

    tony0713 Junior Member
    from pa
    Messages: 18

    with the plow lights on yes. I cleaned up the positive and negative studs on the pump. and dielectric grease in the plugs.
     
  11. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,967

    Need to do a volt drop test. How many volts at the lights,, how many volts at the batt...how many volts at the trk lights...And so on
     
  12. bmc1025

    bmc1025 Member
    Messages: 35

    Look to see where the control wiring was tapped into the fuse box. It may have been tapped into the same circuit as the ecm. Find a different place to tap into the ign feed.