Who knows about FCCC "MMDC" and its issues?
Gents, I've searched and read many issues regarding the old "VDC" units and the newer MMDC units. I'm thinking I may have developed an MMDC issue. Here's the scenario. We're presently on vacation and...
Forum Discussion
"If you could identify the pins on the connector that the wires go to you can see if you have a good connection to the data link by checking the resistance between the two pins. If it is around 60 ohms, you have a good connection to the data link. You want to be sure the other controllers connected to the data link are shut down when you are testing."
Dougmac,
I most certainly appreciate your assisting me with this issue and "coaching" me on some test procedures. If I were at home, I'd have dove into this with both feet. That way, if I screwed something up, we wouldn't be stuck some place in "Nowheresville" and then have to get tow, and all that stuff.
In the time we've owned this coach, I've taken the time to read and learn about the innerds of this beast as much as possible. Some stuff is easy to comprehend. Some, you almost have to be a "Suma com laud" from MIT to grasp the concepts.
Computers have done well in making todays autos a more better, safer and more efficient machine but, they've also made them SERIOUSLY MORE COMPLICATED in terms of searching out problems.
One of the things I learned yesterday was, there's two resistors in the J1939 data link. One is accessed just down line from the rear diagnostic port, just above the radiator. The other, is located INSIDE the MMDC.
Now if this isn't one of the most asinine things done in auto technology, I don't know what is. You see, that little, "$.50" resistor, is INSIDE a $400.00 computer. So, when that little fifty cent resistor goes bad, you get to spend $400.00 and, pay to have it replaced when, I can have that MMDC out of my coach in right at 2 minutes.
But, since I was/and still am, somewhat limited in diagnostic capabilities, I/we the DW and I, are going to take the shaft when it gets replaced today. So, live and learn. And some people wonder why I still change my own oil.
Scott
Dougmac,
I most certainly appreciate your assisting me with this issue and "coaching" me on some test procedures. If I were at home, I'd have dove into this with both feet. That way, if I screwed something up, we wouldn't be stuck some place in "Nowheresville" and then have to get tow, and all that stuff.
In the time we've owned this coach, I've taken the time to read and learn about the innerds of this beast as much as possible. Some stuff is easy to comprehend. Some, you almost have to be a "Suma com laud" from MIT to grasp the concepts.
Computers have done well in making todays autos a more better, safer and more efficient machine but, they've also made them SERIOUSLY MORE COMPLICATED in terms of searching out problems.
One of the things I learned yesterday was, there's two resistors in the J1939 data link. One is accessed just down line from the rear diagnostic port, just above the radiator. The other, is located INSIDE the MMDC.
Now if this isn't one of the most asinine things done in auto technology, I don't know what is. You see, that little, "$.50" resistor, is INSIDE a $400.00 computer. So, when that little fifty cent resistor goes bad, you get to spend $400.00 and, pay to have it replaced when, I can have that MMDC out of my coach in right at 2 minutes.
But, since I was/and still am, somewhat limited in diagnostic capabilities, I/we the DW and I, are going to take the shaft when it gets replaced today. So, live and learn. And some people wonder why I still change my own oil.
Scott
