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light's on?

Discussion in 'Commercial Snow Removal' started by DYNA PLOW, Dec 3, 2001.

  1. DYNA PLOW

    DYNA PLOW Senior Member
    Messages: 295

    here's a good one, 01 dodge 2500, new st5 snoway stainless spreader...anyway i wanted to install a lite on the back off the spreader , bought the lite and mounted it went to hook up the power and the ground, i tapped into the 12v power source sent to the conveyor and spinner clutch cause i only need the lite on when i'm salting. that way i didn't need to run any new wires up to the cab and could use the circuit that was allready there for the clutch. hooked it up and started the spreader, flipped the clutch switch and on went the conveyer and spinner as well as the lite ... cool i thought..... then i happen to look at the front off my truck and my headlites are shining very dimmly, disconnected spreader lite ground and headlites went off. interesting i thought, must be back feeding the headlite circuit on the truck.
    you guys got any ideas?
    dan
     
  2. Pelican

    Pelican 2000 Club Member
    Messages: 2,075

    Check that your ground connection for both the light and the sander are both clean.
     
  3. DYNA PLOW

    DYNA PLOW Senior Member
    Messages: 295

    oh there both clean i mean real clean , iv'e never even used the spreader yet.
    dan
     
  4. CT18fireman

    CT18fireman Banned
    Messages: 2,133

    Is the spreader touching any part of the truck that is steel?

    Sounds like you are completing a path to ground somehow through the spreader and harness. I think Dodge uses a negative source for their headlights now. Did you ground the light to the spreader or the truck? Does the sno-way harness somehow ground the spreader to the truck? Are you getting the power for the clutch from the spreader battery or the truck battery? If you are taking the power from the truck I would think you may need to connect a good ground between the spreader and the truck frame.
     
  5. DYNA PLOW

    DYNA PLOW Senior Member
    Messages: 295

    the spreader is not touching the truck,you are correct that dodge uses negative source for headlites. i took power from the feed wire which gets its power from the control box which gets it's power from the truck battery ,the lite is grounded to the spreader,the snoway harness grounds to the truck thru the control box which is grounded to the truck,
    thanks for your input ,
    dan
     
  6. Pelican

    Pelican 2000 Club Member
    Messages: 2,075

    Let us know what you find, there's gotta be a bad ground somewhere...
     
  7. DaveK

    DaveK Senior Member
    Messages: 420

    Do you also have a plow wired on this truck?
    Does it have daytime running lamps?
     
    Last edited: Dec 5, 2001
  8. DaveK

    DaveK Senior Member
    Messages: 420

    I have thought this through and through. Here is what I believe will solve the problem, although the cause is somewhat of a puzzle.

    I would have to say that the sno-way harness it not grounded to the sno-way unit itself (only the actual components that need a ground, like the conveyor and spinner clutch). And that you grounded the new light to the sno-way unit, not the actual ground wire in the harness.
    So, run a ground wire from the light, to the ground in the harness.

    This opinion is based on a few assumptions. And without knowing the answers to the questions in my prior post.

    I even drew a schematic, and the part that puzzles me is that it simply shouldn't happen if the headlight switch is off. Even if the above solution solves the problem.
    :confused:

    Perhaps we need an electrical engineer. :)
     
  9. DYNA PLOW

    DYNA PLOW Senior Member
    Messages: 295

    Dave K yes the truck has a plow wired on it. no it does not have daytime run lights.
    thanks for your thoughts....however i could not come up with the solution to solve my little puzzle so i simply stole 12v from the hot side on the solenoid and wired the ground thru a switch located on the rear of the spreader.
    as you said it should'nt have done that ,but....i couldn't find the problem. grounding it directly to the harness itself might have solved it, if i get some extra time i will try it just for kicks!
    dan
     
  10. DaveK

    DaveK Senior Member
    Messages: 420

    In effect, that is what you did do.

    Changing to a different power source would not make a difference. And you did run a ground to the harness, even if it was on the switch.

    Still a puzzle, but now the puzzle involves the plow wiring. Probably not worth the time to track it down though.
     
  11. DYNA PLOW

    DYNA PLOW Senior Member
    Messages: 295

    my thoughts exactly....not being worth the time to track it down.
    thanks for your time dave.
    dan
     
  12. DaveO

    DaveO PlowSite.com Veteran
    from Ma.
    Messages: 299

    Dodge headlights

    I think you guys are on the right track. I just finished installing a Fisher setup on my Ram. I had a harness from a 96 F350, did not work correctly and found out about Dodge's "positve gnd" setup. I had to modify the harness, you need to add a couple of relays to it to make it function correctly.

    The way Dodge is wired is the common terminal(gnd) is actually +12vdc. When the deisred beam is selected(hi/lo), that terminal is switched low(to neg). If you test the terminals with the headlight switch off, AND the key/ignition off, you will find 12vdc on ALL 3 terminals on the headlight connector.

    So I believe that somehow your spreader light gnd, found a way to your headlight connections, and gave it a current path to chassis gnd, which allowed the lamps to glow, since there was 12vdc on them already.


    Dave
     
    Last edited: Dec 6, 2001
  13. CT18fireman

    CT18fireman Banned
    Messages: 2,133

    Actually it can be done without relays just have to make sure the bulb does not ground inside the plow light. Toyotas have been wired this way for years. I installed Meyer lights on the Toyota with no relays.
     
  14. DaveO

    DaveO PlowSite.com Veteran
    from Ma.
    Messages: 299

    CT18,

    You are correct. I did not want to disconnect the neg gnd inside the plow light, and run the extra wire. I could have tapped into the running light feed, but felt it was not sufficient for the current needed.

    Another quick/easy way is to not plug in the headlight adapters at all. Take the low beam feed(you have to cut/splice), and wire it to the battery + side using a fused connection(15a). Now when you energize the relays by turning on the parking lights, it turns on the low beams. And you can still run the truck headlights if wanted. Cons are you cannot run ONLY the parking lights, and you have no high beam. But it is a cheap/easy fix.



    Thinking about the measurements I made on the Rams headlights. I would bet that the +12vdc is supplied ONLY to the "common" all the time. The reason I measured it across ALL terminals is because I had disconnected only one headlight plug. The other was still plugged in. The +12vdc was"floating" across the filaments, and both plugs are probably in parallel.

    Dave
     
  15. DaveK

    DaveK Senior Member
    Messages: 420

    Gee thanks. I think DynaPlow already got it fixed.

    That part is already obvious to everyone except for the guys that thought it was magic.
     
  16. DYNA PLOW

    DYNA PLOW Senior Member
    Messages: 295

    guys, here's the thing.. the ground i used is the same ground as before the only thing i switched is the power source. i think dave is right when he says i should ground directly to the spreader harness. thats why it baffled me, same ground just dif. power source.
    dan
     
  17. DaveO

    DaveO PlowSite.com Veteran
    from Ma.
    Messages: 299

    DaveK,


    "I even drew a schematic, and the part that puzzles me is that it simply shouldn't happen if the headlight switch is off."


    I posted this because I thought you had the right answer, but you might be unaware that there is +12vdc available EVEN with the headlight switch off. Pardon moi.


    Dave
     
  18. DaveK

    DaveK Senior Member
    Messages: 420

    You should know by now that you can't assume that I am unaware. :)

    And this statement
    shows that you assumed that none of us understand what a positive ground is. Even though that statement is not totally correct. But to your credit, you did post a corrected statement. :)

    The fact that there IS a plow harness on this truck changes everything though. It would be near impossible for any of us to diagnose the true cause now, since we have no way to know exactly how the plow light harness is installed.

    In any case, the solution I offered will (or would have) fix(ed) it. The one thing that proves that is that the headlight is not on dimly when the conveyor is running. And the only differentiating factor between the new light and the conveyor was the ground wire. Well, the ohms would be different as well, but let's keep it simple.
     
  19. DaveO

    DaveO PlowSite.com Veteran
    from Ma.
    Messages: 299

    DaveK,

    "You should know by now that you can't assume that I am unaware."


    My bad, guess I should have learned that by now. Probably comes from teaching night classes/training courses at various jobs. I always try to break it down to basics for the students to leave less chance of being misunderstood.

    FMI...Is that spreader a gas or electric motor. Not knowing too much about spreaders(except that I want one), what exactly is powered and by what? I know there is a clutch, conveyor, and spinner, are they all powered by a gas/electric motor? Or is there a generator on the gas motors to provide 12vdc to run some of the necessary functions?

    Dave
     
  20. DYNA PLOW

    DYNA PLOW Senior Member
    Messages: 295

    the spreader is powered by a briggs motor, it has a charging system on it to recharg the spreader battery.
    yes when i turned on the conveyor clutch the light would come on and the headlites would shine dimly...however no taillites would come on.
    dan