PTO control wiring seems to have burned up?

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by rolls canardly, Jun 21, 2024.

  1. rolls canardly

    rolls canardly Road Train Member

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    I have a 2007 Freightliner M2-106 26,000 GVW Rollback.
    I was out with my dump truck, and came home to a cloud of smoke coming up from my Rollback.
    Whatever event caused this must have just happened B4 I pulled in.
    It smelled electrical, and I immediately disconnected the battery.
    I had a battery disconnect switch I was meaning to install; this made that install happen.

    I got in and the truck fired right up, and everything worked, except my PTO to move the rollback bed.
    Got it jacked up and looked around and could not find any fried wires??
    The power light for the switch comes on in the dash, but nothing happens.
    You can hear the hydraulic fluid start moving from the pump when it does go on.
    I'm going to rip into the dash tomorrow and see if there is a relay or fuse for this switch.
    Anyone here know a thing or two about this?
    Thanks!
     
    Last edited: Jun 22, 2024
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  3. rolls canardly

    rolls canardly Road Train Member

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    Pulled the dash panel with the switch on it, the wire going to the PTO is a green w/yellow stripe.
    It looks good in the dash. Went up front under the hood and found a wire bundle,
    next to air compressor, with the protective plastic sleeve rubbed thru, but no green/yellow wire.
    I added additional protection and wire tied it away from compressor head. Not related.

    Under the truck there are several connectors that are just hanging; one with a round connector,
    full of dirt, so not used, and another with a two wire oval female - about 8" long,
    that also was not connected, coming out the front of PTO.

    Mystery of the day - where does the green w/yellow stripe wire go???

    I have to do more extensive cribbing and blocking to raise this beast higher to see better.
     
  4. Metalicious

    Metalicious Road Train Member

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    Bad PTO clutch maybe? That would smell kind of electrical, wouldn't it? Not sure how it would burn on its own without running, though.
     
  5. rolls canardly

    rolls canardly Road Train Member

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    I did have a problem with the PTO right after they put a new transmission in,
    they forgot to tighten the clamp on the pump inlet hose to tank, and it was sucking air.

    You bring up a good point. I do not know if I turned the switch off? Don't remember.
    Can the coil on the clutch burn out if left on for a couple hours?

    The clutch did work just fine, It seems there is no power going there from the switch.
    I just happened to pull in as a cloud of electrical smoke was rising,
    but was too late to see where it was coming from exactly.
    Or maybe, as you said, I pulled in just in time to see the clutch fry.
    Or, is there a clutch at all? I thought it was operated hydraulically thru the transmission.
    Maybe the hyd. power to shift it in and out - shifts from a solenoid coil? IDK?
     
  6. Metalicious

    Metalicious Road Train Member

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    Have you checked the fuses? If no power from switch, the light comes you said, though, right? I wouldn't think they hid the fuse for the PTO anywhere special. But I wouldn't know for sure.
     
  7. rolls canardly

    rolls canardly Road Train Member

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    Thanks for the reply.
    Yes, the light comes on when you turn the switch on.
    I doubt there is a space in the fuse block for a PTO, as it is an add-on not commonly used.
    I tore dash apart thinking maybe there was a relay fried, or fuse blown in line.
    Found nothing.
    Green wire w/yellow stripe goes into about a one inch bundle of wire and disappears.
    So, the hunt continues. Looks like today is pressure wash the frame and underside day.

    I had a steam cleaner, but it burnt and caused my total loss garage fire 2 months ago.
    More specifically, the block heater burnt, that I had on the water cooled motor for it.
    Search bar, enter "Garage," for viewing that mess. I'm still in shock from that.
     
  8. rolls canardly

    rolls canardly Road Train Member

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    So.... not much progress on wiring issues. PTO won't work.
    found bundle green wire w/yellow indicator goes into,
    and traced thru firewall down to inside frame.
    gotta cut it open down there tomorrow,
    to find the green wire w/yellow indicator down there
    and see where it goes.
    But, so far, I see nothing burnt or even melted.

    A question for all:
    If I left a solenoid energized for 2 hours, (I forgot to shut it off,) could it burn up?
     
  9. rolls canardly

    rolls canardly Road Train Member

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    replaced coil, all is well.
     
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