Possibility of Repairing SAM Chassis

Discussion in 'Freightliner Forum' started by Cedric62, Jan 11, 2025.

  1. Cedric62

    Cedric62 Bobtail Member

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    Well, to make a long story short, a friend of mine has a 2016 Freightliner Cascadia Evolution with a DD15 motor (last six of VIN HF6666), and I'm now fairly certain that all of our remaining issues are due to a bad SAM Chassis, as we have pretty much eliminated every other possibility.

    So, now I'm wondering if anyone has experience wtih opening up a SAM Chassis unit and repairing it themselves? The reason why I'm inclined to want to open up the SAM Chassis, is because I believe that someone may have over tightened the main supply cables at the bottom of the unit, and now it appears that the stud for the ground connection is not making a good connection internally. - I'm basing this upon the fact that the ground stud appears to be loose and wobbly, while the positive stud does not, and when I put an ohm meter across the two studs, I do not get any signs of conductivity.

    Does anyone happen to have a photograph or a schematic of what I might find if I crack this thing open? It's not working now (classic blinking light issue) so what harm could possibly come from taking a look inside it?
    SAM_Chassis.jpg
     
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  3. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    Are the problems you're seeing related to the functions of the SAM chassis?

    I think I opened one once, but never tried repair as replacement was quick, easy, and more affordable for the customer.
     
  4. AModelCat

    AModelCat Road Train Member

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    Is there a core charge for it and would you lose it if you opened it up?

    That would be what would determine if I'd open it up or not.
     
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  5. Cedric62

    Cedric62 Bobtail Member

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    We are getting the blinking lights all over the exterior of the cab, and also alternating turning signal indicator lights in the dash. Also, the owner told me he has an error code indicating no communicating with SAM Chassis. So, I guess that has got to be it. I know they are available, but this friend of mine is recovering from a debilitating illness, and he doesn't have the cash for a new one.
     
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  6. Cedric62

    Cedric62 Bobtail Member

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    I thought about that as well, but if I could fix it, then the core wouldn't matter. Hmm....It seems like the internal path to ground is broken somehow, but I don't want to dive into it without a schematic or a photo of one. Hmmm
     
  7. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    I don't think the loose ground will be your issue, but for sure then it's SAM chassis related. Any junk yards near you may have one?

    Water infiltration is the most common cause for those symptoms. Any recent storms? Maybe remove it and open it up? Dry it out abd reseal?

    I've never done it, but it's an option.
     
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  8. QUALITYTRUCK

    QUALITYTRUCK Road Train Member

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    In the history of the world water is undefeated.........
     
  9. Cedric62

    Cedric62 Bobtail Member

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    It seems like the only wrecking yards in my area are automotive wrecking yards. I haven't seen any dealing in big rigs, but I guess there must be one or two in this state. I just moved here awhile ago, still finding my way around.

    Also, I do know that he had a leak near the top of his windshield, and he showed me a spont where someone tried to repair the gasket around his windshield by putting black silicone caulk on it. I suspect that the water probably got around the gasket, and then it probably worked its way down the A pillar into firewall area. From there I suspect that it probably got into the SAM Chassis from the inside of the cab, because I don't see an signs of water staining on the side of Sam Chassis located underneath the hood. So, I'm thinking that the water must have gotten in that way.

    On the other hand, if I can locate a used SAM Chassis at a wrecking yard, what sort of obstacles would I face with installing it into my friend's truck? I'm thinking that a SAM Chassis is similar to a body control module found in an ordinary passenger car, which means that it would have to programmed specifically for that particular vehicle.

    From what I understand, you need to have some sort of a paid account with Freightlliner in order to download the necessary software, and then you need a special type of adapter to connect a laptop to the diagnostice port under the dash. Of if I find one with the same six digits in the VIN, can I switch it out and it would work fine?
     
  10. Cedric62

    Cedric62 Bobtail Member

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    Can't argue with that. :(
     
  11. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    Most I dealt with were plug and play that were done on service calls. I do remember one I had to have some programming done to, but I can't remember what year it was, or even if the SAM Chassis was involved.

    It had been struck by lightning, so multiple ECU's were replaced, then we took to the dealer to program.
     
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