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99 ford with fisher SEHP-wiring problem

Discussion in 'Ford Trucks' started by markd3682, Dec 17, 2008.

  1. markd3682

    markd3682 Junior Member
    Messages: 7

    I recently bought a used (1998) M.M. SEHP plow set up for my truck 99 Ford Super Duty with 7.3). We put in the harness according to the schematic from Fisher. I have a problem that the high beam indicator stays on now and when I change to high beams it looks like there is a ground problem (light is at half the intensity). There is no problem with the low beams (on the truck)

    Last night when I hooked up the plow and plugged everything in there was no LOW beams on the PLOW lights just HIGH beams. I'm so confused.

    I talked to Roger at Fisher and he suggested checking the solenoids. I changed both solenoids but no change with the lights. Tried calling Roger back but he must be busy, no call back yet.

    Any help would be appreciated.

    Thanks

    Mark
     
  2. Flipper

    Flipper PlowSite.com Addict
    from CT
    Messages: 1,180

    I would bet the lights are not grounding correctly. What will then happen is they will follow the other wire (high or low) back to ground. There should be a small gauge orange/black wire coming out of the harness and grounded to the motor where the heavy gauge black wire attaches.

    If in doubt take a light assembly apart and run a jumper right to the battery ground from the sealed beam plugs black wire. Don't trust the plow frame to ground the system.
     
  3. markd3682

    markd3682 Junior Member
    Messages: 7

    Would you be talking about the truck lights (not being grounded correctly) or the plow frame lights? The truck lights worked fine until we added the fisher wiring.
     
  4. Flipper

    Flipper PlowSite.com Addict
    from CT
    Messages: 1,180

    The plow lights. The way the lights work is by using the parking lights to switch the relays. When the plow is plugged in if grounded correctly it will throw the relays so that both low and high when selected with work on the plow nstead of the truck. If the lights are not grounding correctly though the parking lights will find ground through the turn signal or high/low beam wires, throw the relays and this is why you may be having problems.

    Look for thr black/orange wire by the SEHP or try a jumper right from the plow light sealed beam plug (in housing), use the black wire and jump to ground on the battery.
     
  5. Monroe74

    Monroe74 Junior Member
    Messages: 20

    check the plugs that you connect together you may have a bent pin
     
  6. markd3682

    markd3682 Junior Member
    Messages: 7

    Thanks for the help and input. I went back and rechecked the (blue) ground wire and found that I had it plugged into the solenoid where the (white-high beam) wire was. You were RIGHT about the ground being bad.

    Thanks again

    Mark