Forum Discussion

StuartT's avatar
StuartT
Explorer
Dec 28, 2017

Allison 12 Volt Supply Wire

At least on Monaco products, the Allison 12 volt supply line is normally taken off the chassis battery with a dedicated wire and in-line fuse. For some reason on my 2006 HR Imperial, that is not the case and I am having trouble finding the source wire. I may have some corrosion or poor connections causing intermittent starting problems where the transmission warning light comes on and code 6340 is thrown. 6340 translates to wiring, switches and/or connector failures.

I have checked the battery compartment and surrounding, the font and rear run bays, all around the ECU, etc. to no avail. My ECU is in the overhead of one of the cargo bays and the harness just disappears into a jungle of wire bundles.

If anyone has a clue for somewhere I haven't looked, I would love some feedback.
Class A
  • wolfe10's avatar
    wolfe10
    Explorer
    Dec 28, 2017
    Stuart,

    Sorry, can't help with your question, but before spending too much time on it, I would consider just pulling a new wire from chassis battery (with fuse at battery end). That way you KNOW that it has a good source of 12 VDC.

    The cost of an Allison ECU makes preventing voltage spikes well worth the effort.
  • StuartT's avatar
    StuartT
    Explorer
    Dec 28, 2017
    Hi Brett,

    That's not a bad idea if I can identify the correct pin to jumper at the ECU. There are three connectors but I should be able to get assistance from Allison I would think.
  • DSDP_Don's avatar
    DSDP_Don
    Explorer
    Dec 28, 2017
    "StuarT".....I'm not sure which particular wires you're looking for, but there is an Allison box in your front run bay. On the right side. When you remove the cover, there are either 6 or 8 Bosch relays in there (at least that's where they were located on my 2005 Diplomat. Might be your issue.

    I also have the schematics for the 2005 for several models. PM me with an email address if you would like a copy.
  • StuartT's avatar
    StuartT
    Explorer
    Dec 28, 2017
    Thanks Don,

    In the Imperial, 2006 at least, the Allison relays and ECU are located in the ceiling of the forward cargo bay. There is nothing related to the transmission in the front run bay that I can see. Hopefully someone will respond with a similar Monaco product wired like mine.

    Thanks for the schematics offer. I will pm you my email and see if there are similarities in any of the related wiring.
  • Executive45's avatar
    Executive45
    Explorer III
    Dec 29, 2017
    StuartT, I'll try to get to the coach later today-we've got company coming for New Year's and trying to get ready. I have all the manuals for the Allison as well as the wiring diagrams for my entire coach. I'll see if I can help. Is this an emergency issue for you? If so, I'll make it a priority on my end. Let me know....Dennis
  • rgatijnet1's avatar
    rgatijnet1
    Explorer III
    Dec 29, 2017
    I somehow doubt that there is a wire that comes from that battery, through an in line fuse, and directly to your Allison transmission. In that scenario, it would mean that you have 12 volts continuously at your transmission without any means to turn it off. I would suggest NOT to run a jumper.
    Having a relay to switch 12 volts off and on to your transmission makes more sense.
  • StuartT's avatar
    StuartT
    Explorer
    Dec 29, 2017
    Dennis, not an emergency. Not moving from El Mirage RV Resort until Monday when we head to Gold Canyon. Probably okay as is to get there.

    rgatijnet1, you make a good point but I can tell you for sure that this is exactly how it was wired on my old 1992 Dynasty. That fuse blew and I was reduced to limp home mode.

    It is likely that the battery supply voltage spec'ed by Allison requires direct battery supply for clean voltage, and it is likely switched by another relay controlled by the ignition. There are several members on another forum discussing ongoing problems similar to mine that have found the wiring to be as I describe. Unfortunately my Imperial seems to be an exception.
  • Executive45's avatar
    Executive45
    Explorer III
    Dec 30, 2017
    Unfortunately, after spending some time looking thru the owner's and the operator's manuals there is nothing about wiring, only code identifiers. Also, my wiring book is from Monaco and it's only for the coach specs not the running gear. I have found, though, most Allison dealers are very helpful.

    StuartT, if you would like to make copies of the aforementioned manuals feel free. I'm in Mesa so we're close to Gold Canyon. Let me know....Dennis
  • StuartT's avatar
    StuartT
    Explorer
    Dec 30, 2017
    I appreciate your taking the time to look into the supply wire issue Dennis. Once I get settled in Gold Canyon, I'll PM you and come take a look at what you have.

    Thanks, StuartT

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