Problem with MMDC display on 2006 Itasca ellipse

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cupe873

Member
Joined
Nov 4, 2016
Posts
15
Hi all
Have a question regarding the MMDC Display on my 2006 Itasca Ellipse. Freightliner chassis, 350 hp cat engine. Pulled into a truck stop to fuel up the other day. when I was leaving I released the air brakes and 3 lights came on and stayed on on the small display center. The high beam and both turn signals. They would only come on when the air brakes were released, but now come on sometimes with the air brake still on. I did a walk around of the rig and everything outside was working head lights, turn signals, brake lights. everything outside worked. Drove it a couple of hundred miles with no problem. Parked it at my sisters house in Chilliwack and made an appointment to get it into the freightliner dealer in Abbotsford. When I started it up to take it to the dealer did a pretrip inspection and I now had no headlights. But everything else worked fine brake lights, turn signals and all clearance lights.

The dealer diagnosed that the light module was defective and ordered one overnight from the states. They changed it over and it made no difference. We were suppose to fly down today to Bellingham Washington and have a commercial driver take the rig and toad down and meet us. we have now cancelled that. I am worried that things would escalate and we might break down on the side of the road. Has anyone had this happen. I am not a mechanic but am leaning towards the MMDC being the problem.
Thanks for any impute.
 

John Canfield

Site Team
Joined
Aug 8, 2006
Posts
13,659
Location
Texas Hill Country
My memory is a bit fuzzy, but two things come to mind - the MMDC (multi mode data controller) isn't available any longer and I think someone pulled theirs and reflowed some solder lands and brought it back to life.

I recommend you call Freightliner and run the symptoms by them.
 

emiddleb

Well-known member
Joined
Mar 22, 2009
Posts
330
John, I believe it was the VDU (prior era box) that had the cold solder problem.

However, a loose connection at the MMDC could cause the OPs issues. Might be worth taking a look at it. Also worth checking the cable at the back of the display to make sure it is tight.
 

cupe873

Member
Joined
Nov 4, 2016
Posts
15
Thanks. It talked to Freightliner and they said it could possible be the MMDC control module, but he didn't sound to sure about it. Told me Freightliner still stock the parts. Could not give me a price but I did find some available on the web. not cheap 800 to 1000. I have a call into the manufacturer Medallion Instrumentation System to ask them some questions. Just waiting for then to return the call. I did look at the connection going to the main module. will check out the other connection.
 

cupe873

Member
Joined
Nov 4, 2016
Posts
15
So it turns out the problem was power feeding back up the Headlight ground wire. The shop replaced the turn signal column control and the HDLP control; module And rewired the grounds for the headlights.
 

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