1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

7 1/2 Fisher MM2 LD - Dead battery

Discussion in 'Fisher Engineering Discussion' started by jcf, Dec 30, 2008.

  1. jcf

    jcf Junior Member
    Messages: 7

    Hello, I have a 1998 Chevy 1500 4x4 with a 2005 7'6" Fisher MM2 LD plow. My battery is less than 1 year old and the connections are corrosion free.

    When the plow is connected and not driven for 24 hours or more, the battery goes dead and I need to jumpstart it. Always starts right up with a jump.

    If the plow is disconnected, I could leave it for 3 weeks and it would start up fine.

    Another note... When I control the plow for a longer than normal period of time (let's say I lift it Up, then drop it, then right angle for 5-6 seconds while plowing forward) the battery gauge drops to between 8-10. It will then quickly build back up to 14ish when I release the controls. I have tried other plows mounted on my truck and experience the same symptoms.

    I have examined the wires and can see no visible shorts. I have tried a spare iso module to eliminate that and it is behaves the same.

    Any thoughts? Thanks in advance.
     
    Last edited: Dec 30, 2008
  2. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    Fisrt problem is that your power source to the controller isnt on a keyed hot and your leaving the controller turned on. Move the red wire under the dash to a keyed hot.

    As for the volt drop, some drop is normal. The motor on your pump is equal to a starter motor and draws just as much so repetiative use will draw on the electricla system. You probably havent done the battery any good by having a constant drain that kills the battery along with frequent jumps to get it going agian. If it keeps working and you keep an eye on the volt gauge you should be good otherwise, throw a new battery in there.
     
  3. jcf

    jcf Junior Member
    Messages: 7

    Thanks for replying. I unplug the fishstick nightly because I wired it hot instead of keyed. If the controller is unplugged, it shouldn't drain, correct?
     
  4. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    Correct! And it is still killing the battery?
     
  5. jcf

    jcf Junior Member
    Messages: 7

    Yes. Would a short drain power? Or just prevent it from working all together?
     
    Last edited: Dec 30, 2008
  6. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    The only thing i could think of that would cause a draw with the plow connected is if the solenoid is shorting out internally.


    Take a multi-meter and check across the large terminals on the solenoid, should read 0.
     
  7. jcf

    jcf Junior Member
    Messages: 7

    That's a good idea. I will do that. Makes sense. Thanks.
     
  8. Buster F

    Buster F Senior Member
    Messages: 208

    I had the same problem on my mm2 and learned that even though i unplugged the fishstick having the keyed power wired constant hot still drained the battery. Try changing it to a keyed source and it may solve your problem - i know it fixed mine. Good luck, Roy
     
  9. Me Too

    Change the red wire to a keyed power source and your problem will be solved. Even if you disconnect the joystick/fishstick, when you plug the headlights in, a relay activates in the iso module. Try it for yourself, truck off, open hood, 3 external plugs all connected, controller disconnected. Plug the multi-pin connector together several times and listen to the iso module box. It will click. It's a decent 12V draw and will kill the best of batteries over time. Good Luck.

    Motorman 007
     
  10. jcf

    jcf Junior Member
    Messages: 7

    Thanks for all the replies. When I get a free minute, I will swap it to a keyed/switched power source. Thanks again.
     
  11. pongo70205

    pongo70205 Junior Member
    Messages: 11

    I have the same problem when the plow is connected the battery drains, the controller/joy stick, is wired to a ignition on only port. also I still have not isolated the head light problem so I don't connect the drivers side light to the plow harnes. its a 3 plug fisher MMII.

    So, by red wire are you reffering to the wire from the fish stick or another wire. we are expecting some snow and deep freez so I would like mount plow before it hits. thanks for your reply.
     
  12. The red wire we are referring to is in the control harness that you feed through the firewall and into the cab. It has a separate red wire that comes out of the harness a couple of feet or so from the end that you plug your controller onto. That wire must be on KEYED power or your batteries will drain.
     
  13. Maine_Train

    Maine_Train Senior Member
    Messages: 462

    I thought the problem had gone away in my '04 Silverado after I replaced the primary battery a few months ago. (I think the second battery was new when I bought the truck, a couple of years ago.) Then after the second time I put the MM2 on it this season and didn't drive it for a day or two, I ended up charging it to get it started. :mad:

    The controller is wired always-on, so that's something I'll get changed, but I was thinking if it just had an LED in it, it wouldn't draw that much. So now I know the explanation for why I had to unplug the controller and the light and motor cables to make it stop sucking power for no apparent reason.

    Thanks.
     
  14. pongo70205

    pongo70205 Junior Member
    Messages: 11

    thanks for the reply , yes that wire is on a keyed power source. and i still have a drain on battery. its also got the isolated system . there are four plugs into the control module under the hood. i connected it myself so i know its connected according to the fisher diagram. but i am not sure about the plow side as it is a used plow and someone has fitted it with a diamond blade on a fisher MM2 frame and insta act pump 3 wire set up