C5 X7 MFD - usual issue (unreadable when warmed up) anyone dug into the MFD itself to repair?

[MattBLancs]

Hi all,

Had a search but though worth a new post. My 2009 C5 X7 MFD is doing what they commonly do and becoming unreadable.

Looking here:
viewtopic.php?t=64446

My Johnson Controls MFD is one of the better ones, but it's still knackered. Has anyone else dug into these units to see if can solve the underlying cause? Have seen mention of adding computer fans etc, but all I can find in detail as to a solution is replacement - either expensive Citroen supplied or riskier but cheap Ali express or eBay sourced items.

I've read also there's many visually identical units - so plenty of error traps for replacement!

What is actually getting overheated? The screen itself?

Thanks for any insights,
Matt

Current item rear sticker

[MattBLancs]

In for a penny...

A look inside

Right, it's getting some extra cooling holes as first mod.

Is lit by LED, wondering if would find old fashioned W5W / T10 5 Watt bulbs inside (or the 1.2 Watt ones in the plastic bayonet fitting) = easy swap to LED for less heat in this little box, but no such luck!

Matt

[GiveMeABreak]

I don't have your VIN so I don't know what system you have. There are different MFDs depending on which Telematics system you have and some are not interchangeable so you are correct in what you say concerning replacements. I would need your VIN to determine the correct one of course.

There is also one other thing which could be the head unit itself. Depending on system there would need to be some tests to determine if it is the graphics chip in the Head unit or the display itself that is at fault though.

[MattBLancs]

Hi Marc,

As requested, VF7**************[VIN obfuscated, can be read by forum staff].

Can the MFD failure be the head unit then, how odd! It seems to be heat related - sunny day = MFD rubbish straight away, cold day works ok then will gradually become illegible during a journey, so was assuming the display itself was playing up.

Thank you

Matt

[xantia_v6]

I would suspect that there is an issue with a soldered joint on the display driver or Flexi connector. Can you operate it while open and selectively heat or cool components?

[GiveMeABreak]

Ok, this is the standard RD4 system you have - no telematics, so an EMF C display. With the additional info you mentioned, I agree with Mike, as the display changes with heat conditions, very likely to be a connection expanding and contracting.

These aren't too bad if replacing. 9821852480 is the part for your vehicle. £380.10 inc VAT new from Citroen, but are available new a lot cheaper:

https://www.ebay.co.uk/sch/i.html?_from ... 0&_sacat=0

Now you have the part number, you can be sure to get a match.

[MattBLancs]

I would suspect that there is an issue with a soldered joint on the display driver or Flexi connector. Can you operate it while open and selectively heat or cool components?

Marc - thanks for the part number, will have a dig.

Xantia_v6 - Selectively heating /cooling - could get some "freezer spray" for cooling. Heating more difficult, have soldering iron or heat gun, neither really the right "scale" for these tiny surface mount components. No obvious damage to the flexible ribbon cable, to my untrained eye anyway.

Super lightweight racing spec MFD ready for reassembly

Need to get my C5 into running condition again then will do a bit more investigative work on this (was hoping for something obviously inside here when taking it apart, whilst battery is disconnected - need to do the long winded pat my head and rub my belly battery reconnect procedure shortly. Is complicated by the fact I've not opened the window (as car is outside and it's "British Summer time" ) so instead get myself shut inside, my wife reconnects the battery terminal and I can do all the key pushing, side light activation etc without opening doors - triggering suspension pump etc.

Matt

[GiveMeABreak]

Don't worry too much about the Window being open - it's only for emergencies in case you need to get access to the inside like the handbrake or something without the battery being connected.

[MattBLancs]

Battery back connected this morning but too busy drained fuel etc and forgot to look how the screen behaved. Wondering if a dry joint on the flexible ribbon cable, my strip down could have temporarily improved it (or equally, killed it off completely!)

Matt