Site Links:
Library Contents Search the Library RV Tech Library Help Page Site Map About Us Tiffin RV Network TRVN Classifieds Campground Reviews Photo Gallery TRVN Store
Library Chapters
Appliances Batteries Boondocking/Dry Camping Chassis Clubs & Forums Electrical Electronics Engines Exterior Maintenance Generators Heating & Air Conditioning Interior Maintenance Misc Items Operating Tips Plumbing Red Bay Safety & Health Storage Supplier Contacts Tires and Wheel Rims Towing Transmissions Weighing


Freightliner's MMDC Information Display System

Near the end of the 2004 model year Freightliner began to use a new warning and information display system on the XC series chassis. This system was manufactured for Freightliner by Medallion Instrumentation Systems and uses the CAN protocol to communicate with the various systems within the Freightliner chassis. Most users immediately noticed the new LCD display that was impossible to read in bright sunlight conditions but this system really consists of 3 separate modules.

The heart of the system is the MMDC module. This module is generally mounted on the floor of the motorhome near the front. If you remove the drawers from the center console you'll see a number of electronics devices located there. The MMDC module is the computer shown to the right. This module will have a pair of wiring connectors that plug into it as well as pressure sensing lines from the two air tanks that supply the coach's air brakes.


MMDC Controller Module

The MMDC computer monitors a wide variety of functions and displays the results on the annunciator display at the top center of the dash. In addition to turn signal and high beam indicators, various warning messages will be displayed and there is a unique lit display for up to 24 different announcements.



Should additional information be needed a third module, the Message Center, will display any detailed error messages on the LCD display. This display will also be used to display and navigate any trip computer functions as set up by the RV owner. While this display is very hard to read in bright sunlight an upgraded white background screen is available from Medallion Instruments as an upgrade.



The MMDC is incorporated into the Freightliner electrical system via a high speed data buss using the CAN protocol. It is not possible to upgrade an older coach model because it is tightly woven into the chassis' electronics systems. If you want more information regarding the operation of this display please select the following link to access the owners manual for this system.


Freightliner MMDC Display Unit Owners Manual


Submitted by Submitted by Mark Quasius - 2/25/06

Click Your browser's "Back" button to return to the previous page
 or chose another category from the side menu.


The RV Tech Library is brought to you by the TiffinRVnetwork

Absolutely No Affiliation exists between this group and Tiffin Motor Homes Inc or the Allegro Club. This website neither endorses or discourages the use or purchase of a Tiffin product. All references, suggestions, comments, etc. contained herein are the opinions/experiences of the posters and not those of Tiffin Motor Homes Inc. or the website administrators.

 Freightliner Custom Chassis       Spartan Chassis       Workhorse Custom Chassis       Ford Chassis

©Copyright 2014 TiffinRVNetwork All Rights Reserved