No power to Allison Shift module

[Skip426]

Originally Posted by cbeierl

I believe that coaches with the MMDC will have the Medallion Info Center (see image below) on the dash, while those with the VDC will not.

Good info Chris , I forgot to mention the dash differences between the two .

My knowledge of MMDC is limited to the info from this side , including the picture of the main module. Note how much it looks like the one in my engine bay picture.

RV Tech Library - Freightliner MMDC Information Display

Without knowing which dash package Wayne has I was reluctant to forward the wiring info I have for a 2001 chassis. Best for him to get info , tied to his serial number direct from Freightliner if possible.

[cbeierl]

Here's another posting that talks about/shows the VDC in the left rear of early 2004 Horizons: Air Gauges, Bad or Not?

If the coach had an MMDC it should be located in the left front compartment (as shown in the Winnebago wiring diagrams)

[GWayne]

Thanks Guys.
Yes no lights on the shift pad. So no "in neutral' message and I do have a VDC. Funny there is a big empty spot in the compartment almost as if they were saving the spot to put the MMDC.
It is starting to snow here so I don't know if the tech will want to work on it tomorrow, but you guys have given me a whole lot more understanding of this system. I might be able to converse with the tech a little more intelligently and maybe save some money.
I will check with the shop before they send out the tech to see if they are going to have the wiring diagram when they come.
Thanks Again
Wayne Ridsdale

[GWayne]

HI all; Had a delay here,
first it snowed then the shop I use had a positive covid case so they had employees away getting tested and isolating. The tech is now scheduled to come out Thursday AM, but the weather forecast is not that great.

In the mean time I realized the voltmeter has not been showing any voltage reading with just the key on. It wiggles a bit as the gauges go through their diagnostics but settles at the bottom showing absolutely 0.
All the lights, fans and accessories are good and when I toggle the switch on the main panel between battery banks, it shows both house and chassis batteries to be good.
I was running the generator to make sure the batteries were well topped up when the tech comes and I noticed the generator worked a little harder when I turned the key on. I think that is probably normal and just from the extra load from the lights and other stuff, but....
So I am thinking it is not in the Transmission ECM or the VIM system ( I did check the fuses in the VIM and switched the relays) but somewhere else in the electrical system. Any ideas where to start??

Thanks again
Wayne Ridsdale

[GWayne]

Hi All,

I thought I shoud bring you up to date on my non starting problems.

I started a new thread called "coach won't start" when I realized some other things weren't working on the bus and I thought it might be something other then the trany module causing the no go. I was partly right, the tech found a corroded wire behind the battery that brought my volt gauge back to life but still had no lights to the shift controls. He bypassed the VIM so I could start the MH and get it to the shop.

Rather then retype everything I hope it's alright to just copy and paste my last post to the other thread that explains what we found and how the MH was fixed ( I hope).

Thanks again for the help.

Hi All:
Sorry it took so long to post the results I just got the MH home last Thursday and noticed the Main Brake lights weren't working and as I hadn't checked them this spring might have not been working all along. I mention this as the main brake lights are controlled in another Bussman box just like the VIM box and just inches away.

Anyway back to the no start problem

I had thought the tech had hotwired to the VIM to get the unit going, but in fact he had by passed the VIM somehow.

When they got it to the shop they determined the VIM itself was the problem and found a used replacement at a company called Visionerv ?? East Bernstad Ky.

I had the VIM at home. Inside it is like a very robust 3 layered circuit board with each layer stamped out of at least 1/32 inch thick metal. It appears all it does is direct various electric currents to and from 4 different bundles of wire going to and from who knows where.

At first it looks good and in fact indestructible until you notice the tinge of green around one of the terminals going to one of the wires leading in or out. then you peer under the connection and you see a little more green and then you see that the 1/32 inch plate is eaten right through. ( I would take a picture but the VIM is in The MH at the shop right now.)

It is a little puzzling though, why, with all the wires running in exposed areas, that the corrosion would happen inside a fairly weathertight fitting where the fittings are good and there is no wear and tear.

Are they going to find the same problem in the other Bussman box when looking for the brake light problem?

Thanks for all the help
Wayne Ridsdale