2008 MMDC Delete and Gauage Replacement

[lakedrum03]

Ditch the MDC. Replace the gauges with analog.

[Jackfrost]

Probably sold the boat. Ha.
it would be nice to have people update so that the rest of us can benefit. I know it.s selfish.

[mike koen]

What was the remedy to fix this problem ?

[Baron515]

Like this.

I dont have these on my 2008, there is a car style fuse holder, one for vdig and one for mmdc, both were fine. Power and ground at the main mmdc connector is also fine.

Anyone thing next step is to replace the mmdc? Or are they unlikely to fail?
The one I have is $140 on GLS
https://www.greatlakesskipper.com/ma...t-gauge-module

[Baron515]

I cleaned up that connector a bit, I have no idea why the gray/clear and black wire were spliced, it seems to have been done to reduce the gauge of the wire for the connector, but it shouldnt have been neccesary. I checked all the pins and all were fine, so I only cut back the bare wire and put on a new pin, and then spliced new wires for the other two.
I found a 4 pin connector by the motor, 3 red wires going to the circuit breakers by the battery switch, and a black wire which was disconnected. I have connected it to ground.
I also checked the other connectors, which seem to terminate and didnt find any corrosion on the pins. Do you mean the corrosion could be in the cap where I cant see it?

Im not sure whether I got bad readings the first time, or reparing those connections helped, but I now have around 8.3v at each of the gauge connectors. Is this correct?
The behavior of the gauges are still the same unfortunatlely, key on, gauges seem like they want to cycle and go up maybe a quarter inch then back down, and dont give any readings.
To others that have had issues, is this similar behavior to what you had?

[mike koen]

Brian , I took both capped connectors apart and VERY CAREFULLY cleaned the terminals and pins. Then reinstalled with anti corrosion chemical . I could not find replacement pins and connectors only the plastic holder itself.

[BrianS]

The MMDC setup on an '04 is a good bit different than the '08. His mostly likely problem are the capped connectors like Mike posted pics of above. While you can take the cap off, you can't take it apart to clean the connections internally. If there is corrosion when you take the cap off, you should replace it. Also, that connector you posted could use some love. Not sure what is going on there. The gray/clear wire, black wire and bare wire carry the CAN bus. The bare wire obviously has some issues. Both the clear/gray and black wire were spliced just before that connector, not sure why that would be there.

I'd take that whole connector apart and rebuild it by cutting back to fresh wire and installed new pins. The parts are cheap on Amazon.

[Benzick]

Like this.

[Benzick]

I’ll try and take a pic of them when I go back out to the boat. Follow the power feed from the medallion, and you will see them. They take small glass style fuses.

[Baron515]

Ill try and take the connectors apart tomorrow and clean up any corrosion.
I dont think I have any fuse holders going into the medallion unit on mine, atleast not round ones.

[Benzick]

2008 MMDC Delete and Gauage Replacement

I had a similar issue this year. It turned out to be corrosion on the two fuse holders going into the medallion unit. They are round, about 2 inches long. Replace the fuses, clean the contacts inside the holder, and try the system. It worked for me.

[mike koen]

Did you take those two connectors apart and inspect the terminals ? Looks like green corrosion on the base of two of those wires.

[Baron515]

I finally got chance to run some tests today. I believe it's bad wiring somewhere but I'm having trouble finding it.
I tested power at the gauge connectors and they all give under 3v, the same at the big connector on the mmdc. I get 12v at the main terminals under the dash, so I believe something between there is causing the issue.
Am I right that the wires for the can bus are the ones with the 1 bare wire? What is the bare wire used for?

Here is a pic of a connector under the dash which i believe is for the mmdc and vdig? It seems to have been messed with by a previous owner, and the bare wire is connected but almost broken.



I checked the other plugs which seem like dead ends, one close to the mmdc and another close to the engine. Both seem fine but the bare wire is quite oxidized. Could this be a problem?

[Baron515]

Thanks for the replies and pics of that connector, I will definitely check that out as it seems that could be it as I have done a complete motor replacement and had to redo alot of the wiring back there. That thread is an excellent help.
Unfortunately I havent had chance to get round to working on it yet, but will be updating here once I do.

[mike koen]

How did you make out BARON515 ? Fixed ?