Replaced IC screen but it's still dark. Any ideas?

[Rockster]

(Sorry for the cross-posting but I originally buried this on page 9 of a thread about the IC replacement and that might be too obscure for a timely response.)

We had an IC that went completely dark a short while ago but because the car was still drivable we figured that swapping out the display with one from ReelDeal and keeping our original board would solve the problem. We did this replacement this past weekend but the problem persists: The display is black but we can put the car in gear, work the turn signals (we hear sound; just no display, of course), and such. Chad from ReelDeal suggested everything he could but the problem seems to be with the car and not his replacement display.

Things we already tried or did include:

• Disconnecting the 12v and the HV battery before beginning, so that's not the issue.
• Quadruple checking the ribbon cables. They're clean and secure. We even cleaned the connectors with isopropyl alcohol and blew compressed air in the receptacles in case dust was affecting the ribbon cables' connections.
• Verified that the two connections on the back of the IC assembly are secure.
• Trying every reboot protocol we could find (scroll wheel reset; IC-specific reset; full reset with brake pedal; disconnecting/reconnecting the 12v and HV battery, etc.). The MCU comes up just fine but the IC stays dark. (We did not try a factory reset from the MCU. That's next on my list to try.)
• Verifying that the 5A fuse for the IC is intact (though that seemed obvious since the IC appeared to still be working behind the scenes).

There was talk in the IC replacement thread of a light of some sort appearing within the IC assembly when it's powered up. We have never seen that light, if that's relevant.

Any ideas what we might be overlooking here? Is there anything else to try?

 

[EVolVEr]

This worked for my IC going dark in 2014 Model S :

Disconnect iPhone from car for a couple of days, and see if ICscreen works correctly.

If so, reconnect the iPhone, but don’t dump your Contacts into car. Bluetooth only.
Apparently, the constant back and forth of the Contact Information is too much for the processor.
Worked for me, and hopefully for you.

By the way, I had the warranty fix from mmc1 to 2 before the IC screen problem began.

Don’t know if it works for Android phones.

 

[Rockster]

Follow-up from the OP here. It was the MCU after all; not the IC. Tesla replaced the MCU (and we went ahead and had them upgrade the MCU to an MCU2) and all is fine. It didn't occur to me that an MCU that seemed to be working fine would cause the IC to not display.