MFD fail, attempted to replace 2x

Hi there,
A few months ago our Prius wouldn't turn off when my wife returned home. So, I held down the power button for a while, and it shut off. Curious, I started it back up, and turned it off again a few times normally. It happened a few days later again, so I then decided to disconnect the battery to kind-of reset it. When I reconnected the battery it all worked, except the Mulit-function Display wouldn't display any consumption data anymore, and displayed 'check connection to air conditioner' when attempting to turn on the heat, and displayed 'Audio off' when trying to play the radio.

Doing a bit of research we figured the MFD got fried somehow, which appears to be common, and decided to order a used one on ebay. I uninstalled our current one, and installed the ebay one, and we had the same exact symptoms with the new one. So, we determined that perhaps the ebay one was faulty or something. So after returning the ebay one, I went in to the original and resoldered the points described in the well documented Hobbit post, and still, no improvement. I then figured maybe the original and the ebay one were faulty, because all internet posts seem to indicate this is a common problem with the 2004 MFD, and perhaps there were other mysterious solder points that needed fixing that weren't documented somehow. So I decided to order a 2005 ebay used MFD and to try installing that - but, the 2005 ebay one still didn't fix the problem!

I've checked and replaced all the relevant fuses.

I'm totally stumped.

I've read about a gateway ECU, and think that might be the next place to look?

 

Thanks exstudent - No trouble with the combo meter, just the symptoms described in the MFD.

 

Thanks 2k1Toaster - 12v Battery tests fine and is healthy. Haven't replaced it in a while, but it's healthy.

 

Thanks dolj - I've gone through that hobbit article and soldered those same points, but that didn't fix the problem either.

Still stumped.