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Plow lights dim on MM1 help please

Discussion in 'Fisher Engineering Discussion' started by Jeremie444, Oct 27, 2013.

  1. Jeremie444

    Jeremie444 Junior Member
    Messages: 24

    I'm sorry if this has been asked before buy I havn't found anything like it. Ok so im in the process of hooking up my plow lights to a Fisher MM1 on a 1995 F250. The plow harness is a 2 plug style. When I take voltage readings at the plow lights, they each have only 4.5 volts. when I disconnect one, the other gets brighter.

    Does anyone have a sheet that has what each pin in the control/headlight harness connector is? How else would I trouble shoot this?
     
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    where are you cking your gnd when your using your volt meter?
     
  3. Jeremie444

    Jeremie444 Junior Member
    Messages: 24

    i'm using the orange and black wire that is the ground on the light harness... I found that the blue wire on the plug in truck side harness was all corroded, fixed it, and now I plug in and the headlights blink with the directional, all sorts of weird stuff happening.

    I'm thinking it's time to just buy a new harness that's not from the mid 90's.. if I can find one for a MM1. Do they even exist?
     
  4. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    they blink like that b/c you are having a gnd issue. ck your gnds and go from there.
     
  5. Jeremie444

    Jeremie444 Junior Member
    Messages: 24

    Ok, I think I've checked all of my grounds on this system. The sol. for the motor has an orange/black wire to the battery neg. The Blue wire in the plug in headlight harness is a ground, and appears to be working well. I have cleaned the two grounds in the plow lights, and the one that is attached to the plow motor. Is there another one that i'm missing?

    But I still have no headlights, high beams/ low beams, it makes no difference.

    When I turn the headlights on low beams one of the relays I have starts making a high pitch buzz/whine. High beams does not work at all.

    The turn signals on the right appear to be working correctly. While when I turn on the left one; the left side blinks bright, and the right side blinks dim.

    Sorry for all the questions, I've never hooked up a plow setup before.
     
  6. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    You have 2 relays correct? Are they the rectangular headlights?
     
  7. Jeremie444

    Jeremie444 Junior Member
    Messages: 24

    Yes it's the two relay system with the old style rectangular headlights.
     
  8. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    Ok. Those are cake. Make sure you have pwr at pins 30 then pin 87a with the low beams on. Connecting the plow will gnd pin 85 switching to plow lights. Also pin 86 is parking light pin. Gets pwr from the parking lights
     
  9. Jeremie444

    Jeremie444 Junior Member
    Messages: 24

    Does the truck need to have push plates setup on it to ground with the plow? i'm just trying to work out the electrical first then get the plates on after. I prolly should've asked this first.. sorry...
    :yow!:
     
  10. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    The lights get gnded throught the main pwr and gnd plug. Then it sends gnd through the 9 pin back to the relay
     
  11. Jeremie444

    Jeremie444 Junior Member
    Messages: 24

    yep that was the issue, plow lights come on like they should, noobie mistake. I didn't have the main power plug connected, I was figuring that it didn't have any effect on the lights..

    Now the issue is that the trucks flash to pass and high beams don't work... it just keeps getting better. :angry:
     
  12. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,971

    Ck your high beam relay
     
  13. Jeremie444

    Jeremie444 Junior Member
    Messages: 24

    high beam relay blew again.. gonna have to check the plow side wiring.